Category Archives: seeds

Sixteen Seed Starting Tips

marigoldsGardeners like to start seeds indoors to get a jump start on warm season plants such as tomatoes, peppers, and melons. They also start seeds indoors to be able to grow plants that have a longer growing season than the season in which they live. Before you begin to sow seeds indoors, read these sixteen tips to have as much success as possible. If you haven’t ordered your seeds yet, here is a list of seed companies.

ONE: The sunlight through your windows will not provide enough light. Use fluorescent tubes from hardware stores or purchase special grow lights but make sure their height can be adjusted. Seedlings are grown an inch away from the light source but as they grow the light source must be able to be adjusted. Lights have to be on for 14 to 16 hours daily but you can use a timer.

TWO: Yes, you can make your own seed starting mix but why? It is easier to purchase a bagged mix made especially for starting seeds – this mix is sterile with enough porosity for seeds to germinate and push through.

THREE: Not every seed should be started indoors. Some should be sown outdoors such as cilantro, dill, carrots, spinach, radishes, beans, and peas. Look at the seed package for instructions.

FOUR: What you use as a container is partially determined by what you are sowing. For example, if you are starting a lot of tomatoes, you can use one large tray because the seeds are likely to germinate and grow at the same rate. If you are sowing a variety of plants, use many small containers because each plant will have a different rate of germination and growth. Use plastic containers with drainage holes, draining excess water into a watertight, plastic tray. These can be small plastic cups, fruit cups, or yogurt cups. Another option is soil blocking.

FIVE: Once you sow and water seeds, you need to keep the seed moist until germination because if they dry out, they are no longer viable. This is why many people use clear plastic domes but remember to remove these domes when you see the seed emerge.

SIX: Water the mix in the container so it is moist before planting the seed. It will likely be hard to get moist, it may take several waterings, letting the water drain through, and tamping down with your fingers until you can sow the seeds. Then water again to soak the seeds.

SEVEN: The most common problem is “damping-off” which is caused by a fungus that thrives in warm, moist environments that are poorly ventilated. You will see pinched stems and seedlings that fall over. There is no recovering from this so one must prevent damping off by using clean containers, fresh water, increased air circulation, and not overwater.

seed packetsEIGHT: Usually, fine seed need light to germinate while larger seeds should be buried; check the seed package.

NINE: Heat mats are only necessary if you are starting warm season seeds in a cold area. Not all plants need this and not all places in the home need extra warmth. If you are starting seeds in a very warm room in the house (maybe upstairs – heat rises) you should be fine. If you are using a cool basement, you may need a seed heating mat. However, once the seeds have emerged, they can tolerate cooler temperatures.

TEN: Always label and keep records–within weeks you won’t remember anything. Because the small containers will be close together and under the light, you may want to mark the containers with a black magic marker instead of using plant tags at first.

ELEVEN: What you will see first is not the true leaves but the cotyledons. These once were the halves of the seed. They will look like leaves but soon they will shrivel and die off. Then you should see the first set of true leaves that can begin the photosynthesis process (i.e., make its own food). Decrease watering as you see growth emerge because really the roots are now down deep in the container taking up water so the surface can look a little drier than when you first sowed.

TWELVE: If you planted too many in one container, you can transplant seedlings into other containers after you see this first set of true leaves. Alternatively, you can remove the weakest looking ones with small scissors, just cut across at the base of the soil, do not pull it out.

THIRTEEN: When to start the seed indoors under lights? First determine your average last frost date for your area. Then count backwards the number of weeks given on the seed package. For example, if I use Mother’s Day as my average last frost date then I would start Black Krim tomato seed 6 weeks prior so it would be the last week in March. In that six-week timeframe, I know that probably the last 2 weeks, end of April, beginning of May, I will have moved the seedling to a larger 4-inch pot and place outside on the deck. This period will allow it to harden off.

FOURTEEN: Some seeds have to go through a scarification process where the seed coat either has to be nicked with a file or the seeds have to soak in a container of water for 24 hours before they are sown. For example, soak morning glories in water overnight before you sow them to help the process of breaking down the seed coat and letting the water in. Other seeds need to go through a stratification process of moist, cool temperatures several months before they will germinate. These seeds can be stored in the fridge for a few months before you attempt to sow them. Seed packets should state these requirements.

FIFTEEN: The caveat to #14 is that the seed packet is small and can only offer so much information, so read more information on the company’s website or catalog, or search on the internet, or look in a gardening book in order to have as much knowledge and success as possible for that particular plant.

SIXTEEN: Often there is too much seed in a packet. Don’t think you have to sow all the seed in the packet. In fact, save some in case your initial planting does not work out, or share/swap with friends, or use next year. Most vegetable seed will be viable next year with the exception of onions and leeks.

Good luck!

Sowing Sugar Snap Peas

March is the time to grow peas here in Northern Virginia. I prefer the sugar snap peas where you eat pea and pod together but shelling peas and snow peas also are sowed during March’s cool weather.

St. Patrick’s Day is my cue to soak the seeds in water overnight. Although this is not required, in my experience, it helps to prevent rotting which may occur if I were to plant the dry seeds in the cold soil. Soil temperatures should be at least 45 degrees in order to germinate. 

After the seeds have soaked, there will be a few that have floated to the top of the water. These should be thrown away. They are not viable and will not germinate. Then drain the water off and place the now plump seeds in moist paper coffee filters or paper towels in zipped plastic bags. I leave them on a shelf, I do not put them under grow lights. Within two days, the seeds will have germinated.  Plant them outside along a trellis, about 4 inches apart and 1 to 2 inches deep.

I don’t use an inoculant but you can if you want too. Peas have the ability to “fix” atmospheric nitrogen through nodules on their roots, which means that they can convert the atmospheric nitrogen into a form useable by the plant, thus giving the plant more nitrogen. The peas have a symbiotic relationship with soil bacteria called Rhizobium.  The inoculation usually is a powder form of this bacteria and once applied it encourages formation of the nodules on the plant roots, which increases the capacity to fix the atmospheric nitrogen. The inoculant can be applied to the wet peas after soaking or mixed into the soil where they will be planted. The inoculant is supposed to provide the plant more nitrogen therefore they will be larger with increased yields plus the soil will get a nitrogen boost for future crops. The con of course is that it is an added cost.

Peas need to be planted in full sun with a trellis system. They can be planted in the ground, raised beds, or containers on the deck or patio. Peas have a shallow root system so the container does not have to be too deep. Keep in mind that a container will dry out quicker though. There are also dwarf forms and bush forms that may not need staking. Peas can take a light frost in March and April — you don’t have to run out and cover them for the night.

The flowers are edible and are great in green salads or as a vegetable garnish. However, if you pick them you will not get peas. The young shoots can be eaten as a vegetable or added to green salads. Ripe peas should be picked as soon as possible — the more you pick, the more you get.

This is a great vegetable for kids to grow. The seeds are large enough that they can easily sow and harvest them. Try growing peas this year. To purchase seeds or small plants, check out these seed companies or visit your local garden center.

Winter Sowing 101

It is time for winter sowing! Winter sowing is a method of starting seeds outside in plastic containers in the winter so the seeds will have germinated by spring. In the spring, you transplant the seedlings to your garden bed. There are many advantages to winter sowing. It enables you to start seeds without indoor lights, get a jump on cool season plants, and provide the seeds’ requirements for stratification (a cold period) for those perennials that need it in order to break dormancy. Of course growing from seeds is more economical and provides a wider variety of plants from which to select.

Winter sowing is ideal for perennials, hardy annuals, semi or half-hardy annuals, and the cool season greens, veggies and herbs. Hardy annuals can tolerate cold soil and weather down to the 30’s, such as light frost and moderate freezing. Most hardy annuals expire in the beginning of the summer – they do not like the heat. Examples of hardy annuals are calendula, cornflower, annual larkspur, and pansies. Semi or half-hardy annuals can tolerate cool temperatures and cool soil down to the 40’s; they are damaged by frost. They too do not like the summer’s heat. Examples are baby’s breath, bells of Ireland, blue sage, forget-me-knots, and strawflower.

Cool season veggies, greens, and herbs include lettuce, peas, beets, radishes, broccoli, spinach, parsley, cilantro, and chervil. It is possible to winter sow the warm season veggies such as tomatoes and peppers but for these you would start later in the season.

Usually, seed packets and catalogs will not mention “winter sowing” but if you read the descriptions, you will see clues as to what plant would benefit from winter sowing. Look for words such as:

  • Hardy
  • Withstands frost
  • Self-sowing
  • Colonizing
  • Stratification required (cold period)
  • Scarification required (nicking or soaking in water)
  • Direct sow in early spring/late fall
  • Sow as early as the ground can be worked

In the DC metro area, we start winter sowing on or after the winter solstice which is December 21 and any time through January. It is January now and I have already started several milk jugs of seeds. There is no need to count days or weeks from average last frost date like you would if you were to start annuals under lights indoors.

To start winter sowing, look for plastic containers that can hold 3 to 4 inches of soil with about 2 to 3 inches headroom for the seedlings. You will often see gallon milk jugs but there are other options:

  • Clear, not opaque gallon milk, water, iced tea, juice, or apple cider jugs
  • Large plastic container of pretzels or Twizzlers that come in bulk size for the office
  • Coffee cans (cover with plastic)
  • Plastic container used to sell a roasted chicken (has a high dome)
  • 2-liter plastic soda bottles
  • Large plastic ice cream containers

Assuming you are using a gallon milk jug, make sure it is clean first and throw away the cap (do not need to cover the top).

Create several drainage holes in the bottom with a knife, exacto knife, box cutter, electric drill, or a hot glue gun without the glue.

Using a blade or scissors, cut around and below the handle or about 4 inches from bottom. Do not cut all the way across; leave a hinge on the handle side.

Fill the jug with 3-4 inches of potting mix. Do not use seed starting mix. Do not use soil from the ground or compost pile and do not use bagged soil with “moisture control” or water storing crystals. PRO-MIX works well.

Water the soil and sow seeds of one variety per container. If they are very fine seeds, press down so is in contact with moist soil. If very large, like coriander, press down, cover with a thin layer of soil. Water again and make sure seed is in contact with moist soil.

Close up the jug with duct tape and label or mark it some way so you remember what you sowed. Sharpies will fade so try grease pencils, colored nail polish/paint, or different colored ribbons. I used old lanyards and colored pipe cleaners from craft projects, tied around the handles.

Place the jugs outside in full sun where they can collect rain or snow. It is not necessary for it to snow in your area for this to work. Periodically check to make sure they are okay — dogs or foxes did not tip them over. You will have to make sure they have enough moisture. If it has not rained or snowed, you may have to add water through the opening. If you lift the jugs and they feel light, they will need water. If on a warm day you do not see any condensation in the jugs, you may want to add more water.

In the spring, you should see seedlings. When they are a few inches tall, or when they have two sets of real leaves, open up the containers and let the seedlings sit in full sun for a few days.

Depending on the plant’s preference for cool weather and the size, you may want to move the seedlings to a larger container to let them continue to grow or you may want to transfer to the garden bed. Also depending on the seedlings, you can either pick out individual seedings or take a hunk or chunk (like carving brownies). It really depends on the size/width of individual seedlings (i.e., if thin and fragile may want to take a chunk but if the stems are stout and strong, you can transfer each one). Needless to say, it also depends on your patience.

Try winter sowing this year, you still have plenty of time to get your containers, soil, and seeds.

Seed Swaps: Fun Way to Get New Seeds!

It is that time of year again — seed swaps! National Seed Swap Day is Saturday, January 31, 2026. This is celebrated annually on the last Saturday in January. Seed swaps are a great way to obtain new seeds, share your favorite seeds, and attend a fun event. A seed swap can be as simple as friends getting together to share seeds they saved from the previous gardening season to an all-day planned event with speakers, door prizes, and refreshments.

Seed swaps can be a vehicle to teach others how to save seed, the importance of seed diversity, heirloom seeds, and other aspects of gardening. Some events exchange more than seeds. Tables may be set up to collect used gardening books, magazines, tools, pots, and nursery catalogs. Some may expand their definition of seeds and allow bulbs, rhizomes, and cuttings. Others include related activities such as learning to make handmade seed envelopes.

Each seed swap is different but usually organizers have established guidelines for the seed such as the type of container to use, the number of seed in each bag, and the information required on the label. Organizers should clarify if commercial seed packages or hybrid seeds are accepted. Although swaps do not want seeds from invasive plants, the organizers should clarify the definition of an invasive plant in their area.

If you are interested in attending a seed swap, ask your local county extension agent or Master Gardeners if they know of seed swaps in your area. If you live in the DC metro area, Kathy Jentz, publisher of the Washington Gardener Magazine and founder of National Seed Swap Day, will host a seed swap at Green Spring Gardens in Virginia on February 7, 2026; and Brookside Gardens in Maryland on January 31, 2026. Tickets are available via Eventbrite. For Green Spring Gardens, register here and for Brookside Gardens register here.

If you are interested in starting a seed swap, visit a few first to see the range of activities that could take place and the number of volunteers required. Read Seedswap: The Gardener’s Guide to Saving and Swapping Seeds by Josie Jeffery and the Seed Savers Exchange’s article on How to Organize a Seed Swap. This online article also links to a presentation that Kathy provided at the 2024 Seed Savers Exchange’s conference entitled “Growing Together: Sharing Seeds, Skills, and Stories.” Seed swaps are fun and you come home with plenty of seeds to get you started for the 2026 gardening season.

Hooked on Flowering Tobacco Plants

flowering tobacco white flowers

Nicotiana alata in summer

This year I grew a type of flowering tobacco called scented jasmine (Nicotiana alata). I purchased the seed from Renee’s Garden and sowed them indoors in the spring under lights. It is now November and the 3-foot-tall plants are still blooming, unfazed by cool nights and strong winds. The long, white trumpet-shaped flowers open when the sun goes down, facing me like beacons of light. They are known for their sweet scent which I am sure the night pollinators can pick up. Our winters are too cold for this variety to overwinter. The plants self-seeds but mine are hanging over the lawn’s edge so I doubt I will see more next year. However, I have been saving the seedheads since summer.

Nicotiana alata on left and Nicotiana sylvestris on right, in November

I grew another species called woodland tobacco or as Botanical Interests labeled it: Indian peace pipe (N. sylvestris). Again, easy to sow and grow. I transplanted several plants throughout the garden — some flowered this summer while others just produced a rosette of large leaves. Those that flowered were about a foot taller than N. alata and had similar white trumpets blooming at dusk. However, the blossoms faced downward so it was hard to see the face of the flower. Nice plants but I prefer N. alata smiling and saying hello to me every evening when I come home from work.

I am now hooked on flowering tobacco plants and want to try more next year. In the genus Nicotiana, there are about 60 species including the real (smoking) tobacco. Real tobacco grows up to 5 to 6 feet but most of what we call flowering tobacco plants are shorter, making them the perfect size for the home garden. The flowers have five petals that are fused to create the tubular shape. Many will open their flowers at dusk so you will be able to enjoy them in the evening and early morning. They attract moths, hummingbirds, and butterflies. The plants need well drained soil with more moisture than not (I had to water mine when we had dry spells here in Virginia). They are better in part sun/part shade, and don’t need to be pruned, deadheaded, or fertilized. I never had a pest/deer/rabbit issue. Usually, you must start the species from seed because garden centers do not sell them in containers. However, garden centers sell containers of compact hybrid plants that have been bred to open their flowers during the day.

Bronze Queen flowering tobacco

Bronze Queen, photo courtesy of Botanical Interests

For the 2026 gardening season, Renee’s Garden is introducing Lime Green, a form of N. alata with green flowers. There is another heirloom green flowering type called Langsdorf (Nicotiana langsdorffii) which grows higher at 3 to 4 feet with very long slender tubes. Botanical Interests has a variety of N. langsdorffii called Bronze Queen with chocolate-purple flowers. I prefer the chocolate (who doesn’t) to the yellow-green.

Baker Creek Heirloom Seeds also sells Bronze Queen. They have other forms of N. alata: Purple Perfume with dark purple flowers, Crimson Bedder with cherry flowers, and Sensation Mix with a mix of pink, red, lavender, rose, and white flowers. They also carry Marshmallow (N. mutabilis) where the flowers are rose to cream with very dark throats or centers. This plant grows very tall, up to 5 feet.

Select Watercolors flowering tobacco

Select Watercolors, photo courtesy of Select Seeds

Select Seeds has the largest variety of heirloom flowering tobacco plants including some unusual species.  They sell Select Watercolors (N. x sanderae) which reminds me of when the Queeny series of zinnias came out – a complete game changer. Select Watercolors blooms flowers with muted, antique looking shades of green, pink, lavender, and blush white. Cranberry Isles (N. x sanderae) has pink and purple flowers. These plants are relatively short at 2 feet tall. They also have a N. mutabilis called Select Misty Dawn with white, rose, and pink flowers and Bella which is a cross between N. alata and N. mutabilis with white, pink, and rose flowers. Select Misty Dawn should be very tall while Bella should be shorter at 3 feet.

It is hard to pick which one I want to grow next year but one thing is for certain, these plants are winners in the garden. They perform well despite Virginia’s hot and humid summers, bloom from summer through fall, come in a variety of sizes and flower colors, and are relatively pest and disease free.  Try growing some from seed next year and you will be pleasantly surprised.

Planning for Winter Sowing

Now that some companies are starting to mail their 2026 catalog of seeds*, don’t forget to order some seeds for winter sowing. Winter sowing is a method of starting seeds outside in plastic containers in the winter so the seeds will have germinated by spring. In the spring, you transplant the seedlings to your garden bed. There are many advantages to winter sowing your seeds. You can:

  • start seeds without indoor lights;
  • start plants from seeds which is more economical;
  • start plants from seeds so you can take advantage of a wider selection of plants;
  • provide stratification (a cold period) or scarification (breaking the hard seed coat) for seeds that need it in order to break dormancy; and
  • get a jump on the cool season plants so they are able to flower or thrive in the spring before the summer’s heat.

Winter sowing is ideal for perennials, hardy annuals, semi or half-hardy annuals, and the cool season greens, veggies and herbs. Hardy annuals can tolerate cold soil and weather down to the 30’s, such as light frost and moderate freezing. Most hardy annuals expire in the beginning of the summer – they do not like the heat. Examples of hardy annuals are calendula, cornflower, annual larkspur, and pansies. Semi or half-hardy annuals can tolerate cool temperatures and cool soil down to the 40’s; they are damaged by frost. They too do not like the summer’s heat. Examples are baby’s breath, bells of Ireland, blue sage, forget-me-knots, and strawflower.

Cool season veggies, greens, and herbs include lettuce, peas, beets, radishes, broccoli, spinach, parsley, cilantro, and chervil.  Usually, one does not winter sow the warm season veggies such as tomatoes and peppers.

Seed packets and catalogs will not mention winter sowing but if you read the descriptions, you will see clues as to what plant would benefit from winter sowing. Look for words such as:

  • Hardy
  • Withstands frost
  • Self-sowing
  • Colonizing
  • Stratification required (cold period)
  • Scarification required (nicking the seed coat or soaking seeds in water)
  • Direct sow in early spring/late fall
  • Sow as early as the ground can be worked

In the DC metro area, we start winter sowing on or after the winter solstice (December 21) and any time through January. There is no need to count days or weeks from average last frost date like you would if you were to start annuals under lights indoors.

To start winter sowing, look for plastic containers that can hold 3 to 4 inches of soil with about 2 to 3 inches headroom for the seedlings. The one-gallon plastic milk jugs are commonly used but there are other options:

  • Clear, not opaque, one-gallon jugs of milk, water, iced tea, juice, or apple cider
  • Large plastic container of pretzels or Twizzlers that come in bulk size for the office
  • Coffee cans (cover with plastic)
  • Plastic container used to sell a roasted chicken (has a high dome)
  • 2-liter plastic soda bottles
  • Large plastic ice cream containers

Assuming you are using a one-gallon milk jug, make sure it is clean first and throw away the cap (do not need to cover the top).

Create several drainage holes in the bottom with a knife, exacto knife, box cutter, electric drill, or a hot glue gun without the glue.

Using a blade or scissors, cut around and below the handle or about 4 inches from bottom. Do not cut all the way across; leave a hinge on the handle side.

Fill the jug with 3-4 inches of potting mix. Do not use seed starting mix. Do not use soil from the ground or compost pile and do not use bagged soil with “moisture control” or water storing crystals. PRO-MIX works well.

Water the soil so it is moist. Sow seeds of one variety per container. If they are very fine seeds, press down so is in contact with moist soil. If very large, like coriander, press down, cover with a thin layer of soil. Water again and make sure seed is in contact with moist soil.

Close up the jug with duct tape and label or mark it some way so you remember what you sowed. Sharpies will fade so try grease pencils, colored nail polish/paint, or different colored ribbons. I tie old lanyards from conferences and old colored pipe cleaners from craft projects around the handles. I then write down which one signified which seed. Always keep a record of what & when you have sowed on paper or on your computer.

Place the jugs outside in full sun where they can collect rain or snow. It is not necessary for it to snow in your area for this to work. Periodically check to make sure they are okay. Dogs or foxes may tip them over.

Throughout the season, make sure they have enough moisture. If it has not rained or snowed, you may have to add water through the opening. If you lift the jugs and they feel light, they will need water. If on a warm day you do not see any condensation in the jugs, you may want to add more water.

In the spring, you should see seedlings. When they are a few inches tall, or when they have two sets of real leaves, open up the containers and let the seedlings sit in full sun for a few days.

Depending on the plant’s preference for cool weather and the size, you may want to move the seedlings to a larger container to let them continue to grow or you may want to transfer to the garden bed. Also depending on the seedlings, you can either pick out individual seedings or take a chunk (like carving brownies). It really depends on the size/width of individual seedlings (i.e., if thin and fragile may want to take a chunk but if the stems are stout and strong, you can transfer each one). Needless to say, it also depends on your patience.

Try winter sowing this year. Get your containers, soil, tape, and seeds now so you are prepared to go out right after Christmas!

*Here is a list of seed companies and the following are some of the earliest seed companies to mail their 2026 catalogs:

High Mowing Organic Seeds (will mail in November)
Seed Savers Exchange (will mail in November)
Baker Creek Heirloom Seeds (will mail in December)
Kitchen Garden Seeds (will mail in January).

Saving Cucumber Seeds

These North Carolina heirloom cucumbers from Seed Savers Exchange may look a little funny, but they are easy to grow and very tasty. I pick them when they turn yellow, rub them to remove the little spines, and then peel and eat. This is an heirloom cucumber. I can save the seeds to sow next year. To save the seeds, the cucumber must be botanically mature. That is, the fruit must be mature, and seeds must be fully developed. This is a more mature stage than when most people like to eat their cucumbers. Leave a few on the vine until they turn orange, become bloated, and pull off easily. Then cut open lengthwise and scoop out the seeds.

Put seeds in a glass jar. Cover with water by several inches. Let sit at room temperature for a few days with no lid. It should ferment. Then remove the fermentation and clean the seeds by adding water and mixing and pouring a little off at a time. Rinse and repeat. Eventually the non-viable seeds will pour out and the viable seeds, which are heavier, will stay at the bottom. Do several times until water is clear.

Place seeds on paper coffee filters or cookie sheets to dry. If seeds snap when you bend them, they are dry enough. Store them in an airtight container in a cool dark place. Don’t forget to label and date because you will never remember. Here is a link to more seed saving methods.

The Seed Savers Exchange has a virtual seed saving class from September 29 through November 3, 2025. I took this six-week course last year and it was well worth it. Sessions are recorded and there are plenty of opportunities to ask questions. The curriculum follows along with the book, The Seed Garden, which I purchased because I knew I would use it as a resource for years to come. Registration is open now. If you are interested in saving seeds, this is a great introduction.

Twenty-One Tips for Growing Tomatoes Successfully

By now you should have started your tomato seeds indoors under lights. This is just if you want a head start of course, it is not necessary. You can also purchase tomato plants but be aware that the night temperatures are still cold for them to be out in the garden now. They prefer warmer weather. Waiting to plant tomatoes until the beginning of May or Mother’s Day will give you the best results. For tomato success, read these twenty tips for growing tomatoes in the Washington DC metro area.

First, know what you grow. Tomatoes have determinate or indeterminate growth habit. Determinate types produce fruit at the end of the branches so most of the crop ripens at one time and you will have one or two harvests per growing season. This is advantageous for canning. The determinate types are more compact and are better for containers than the indeterminate tomato plants; however, you may still have to stake the vines or add a trellis. Indeterminate plants produce fruit along the branches so you can pick tomatoes all season long. They can be large, vining plants; a support system such as hoops or stakes should be used.

Sun Dipper, from PanAmerican Seed Handpicked Vegetables.

2. Tomatoes come in many sizes, shapes, colors, and flavors. Grow what you like to eat or use in the kitchen. For example, determine if you prefer to use tomatoes for salad, snacking, pasta sauce, sandwiches, etc. There are more specialized varieties for specific uses such as the Sun Dipper pictured to the right which is elongated to make it easier to hold while dipping into a dip.

3. If you are limited to containers, grow the determinate type and use a container at least 5 gallons large with drainage holes or an Earthbox. Or look for varieties especially bred for containers such as window box types (usually these will be the small, cherry types).

4. Determine if growing an heirloom plant is particularly important to you. Heirlooms may be tastier, and seeds can be saved for next year, but these plants may be more susceptible to diseases. Hybrids are often bred to be disease resistant. However, if you save and sow the seed next year, the plants may not have the same traits as before. Seed catalogs and packages often have letters after the plant’s name to indicate disease resistance. For example, F is for fusarium, V for verticillium, LB for late blight, TMV for tobacco mosaic virus, and N for nematodes.

tomato

Early Girl gives you fruit earlier than most other tomato plants, photo courtesy of Ball Horticultural Company

5. Days to maturity is the number of days it will take on average for a transplant to produce a tomato (fruit) when planted in the beginning of the summer. It is not the number of days from seed. This varies quite a lot with tomatoes from plants with a lower number of days which will provide an early season harvest, to mid-season, to those with larger numbers, resulting in a late season harvest in late summer. If you have the space and want tomatoes throughout the growing season, you can plant early, mid, and late season plants.

6. If starting from seed, sow seeds about a month before average last frost date (Mother’s Day here). Start inside under lights. When the seedlings produce a set of true leaves, you can pot up the plant into a larger container and put outside for a few hours a day. Gradually introduce seedlings to more daylight and more time outside in order to harden off before putting in the ground. Hardening off is the process of acclimatizing seedlings to higher light levels, cooler (than your home) temperatures, and breezes so they can withstand being outside. Here is a link to tips for starting seeds indoors.

7. At first the nighttime temperatures may be too cold (forties and below) to leave these transplants outside so you may have to bring the pots inside for the night.

8. Seedlings and transplants in the spring may develop purple tinged leaves which means cool temperatures are preventing phosphorus absorption. In the summer, when it gets warmer, they will grow out of this so no need to do anything.

tomato

The purple coloring on Indigo sun tomato is intentional, it is a higher level of anthocyanins, which is healthy for you, photo courtesy of Ball Horticultural Company

9. Tomato plants need at least six hours of sun and like warm soil, which is why it is best to put the transplant in the ground after Mother’s Day. If you plant them in cold soil, they will sit, unhappy.

10. Tomatoes like fertile, well-composted soil, not clay. In this area, you may have to amend your garden bed with compost. In the spring, a raised bed and a container will have warmer soil than the ground.

11. When nighttime temperatures are in fifties and the transplant is hardened off, plant in ground. For the indeterminate types, insert staking or hoops immediately after planting. Make sure you have spaced your tomato plants so there is a minimum of 2 feet apart for air circulation (to decrease a pathogen’s ability to spread).

12. Tomato stems will develop roots if covered with soil. Some gardeners will bury as much stem as possible to encourage root production. The theory is that if there are more roots, the plant will be able to take up more water and nutrients. Some people lay the transplant down on the ground, horizontally, burying the stem, but leaving 1 to 2 set of leaves above ground. Some people plant vertically, but very deep, leaving 1 to 2 sets of leaves above ground. Before you submerge the stem, strip off the leaves and little branches that would be underground.

13. A lot of gardeners add calcium in the form of crushed eggshells to the soil or 1/4 cup of lime before planting to prevent blossom end rot. If you do not do this, then pick a fertilizer especially formulated for tomatoes because it should have the added calcium.

14. In the beginning of the summer, mulch with straw, leaves, or compost to prevent weeds and to keep a constant level of soil temperature and moisture. Try Maryland’s Leaf-Gro; do not use composted manure.

15. Tomatoes will need to be watered so make sure a hose or watering can is available. Water the soil, not the plant, and water in the morning to decrease possibility of fungal disease. It isn’t that tomato plants need a lot of water, it is that the soil moisture must be consistent, and not fluctuate often. Mulching helps with this.

tomato

Think of how much water, sun and fertilizer it will take to produce this large slicer, Beefmaster. Photo courtesy of Ball Horticultural Company.

16. In mid-summer, tomatoes will need to be fertilized, especially if grown in containers. Espoma has organic Tomato-Tone and Neptune’s Harvest has a Tomato and Vegetable Formula.

17. To obtain fruit, temperatures must be above 55 degrees at night but temperatures of 75 or higher will inhibit fruit set and may cause blossoms to drop. However, there are heat-tolerant varieties.

18. Tomatoes are wind pollinated. Some gardeners hand-pollinate with a paintbrush if they feel the plant is not setting fruit. All the more reason why there should be good air circulation. Harvest frequently to encourage plants to produce fruit.

19. Pruning is optional, but only indeterminate plants should be pruned. Pruning here refers to removing the side shoots or suckers. Some gardeners do this to increase or to have more uniform fruit size and to help tomatoes ripen faster. It will not increase the number of tomatoes. If prune, start when plants are about 2 feet tall and suckers are small. Do this when the plant is dry, not wet from rain.

20. If possible rotate crops to prevent soil-borne diseases. If your tomato plants are having problems, check out the Virginia Tech Extension site on growing tomatoes, tomato diseases, and tomato pests; and the University of Maryland Extension site on tomato diseases, pests, and nutritional issues, growing tomatoes, and tomato topics; or contact your local extension agent.

21. Pick the fruit when it begins to color and bring inside. Ripen at room temperature and do not put in the refrigerator. This also prevents animals from eating the fruit before you do.

Tips for Starting Seeds Indoors

marigoldsIts time! The month of March is a good time to start many seeds indoors under lights. You can get a head start on warm season plants such as tomatoes and peppers. Before you begin to sow seeds indoors, check out these tips to ensure as much success as possible. If you haven’t ordered your seeds yet, here is a list of seed companies.

ONE: The sunlight through your windows will not provide enough light. Use fluorescent tubes from hardware stores or purchase special grow lights but make sure their height can be adjusted. Seedlings are grown an inch away from the light source but as they grow the light source must be able to be adjusted. Lights have to be on for 14 to 16 hours daily but you can use a timer.

TWO: Yes, you can make your own seed starting mix but why? It is easier to purchase a bagged mix made especially for starting seeds – this mix is sterile with enough porosity for seeds to germinate and push through.

THREE: Not every seed should be started indoors. Some should be sown outdoors such as cilantro, dill, carrots, spinach, radishes, beans, and peas. Look at the seed package for instructions.

FOUR: What you use as a container is partially determined by what you are sowing. For example, if you are starting a lot of tomatoes, you can use one large tray because the seeds are likely to germinate and grow at the same rate. If you are sowing a variety of plants, use many small containers because each plant will have a different rate of germination and growth. Use plastic containers with drainage holes, draining excess water into a watertight, plastic tray. These can be small plastic cups, fruit cups, or yogurt cups. Another option is soil blocking.

FIVE: Once you sow and water seeds, you need to keep the seed moist until germination because if they dry out, they are no longer viable. This is why many people use clear plastic domes but remember to remove these domes when you see the seed emerge.

SIX: Water the mix in the container so it is moist before planting the seed. It will likely be hard to get moist, it may take several waterings, letting the water drain through, and tamping down with your fingers until you can sow the seeds. Then water again to soak the seeds.

SEVEN: The most common problem is “damping-off” which is caused by a fungus that thrives in warm, moist environments that are poorly ventilated. You will see pinched stems and seedlings that fall over. There is no recovering from this so one must prevent damping off by using clean containers, fresh water, increased air circulation, and not overwater.

seed packetsEIGHT: Usually, fine seed need light to germinate while larger seeds should be buried; check the seed package.

NINE: Heat mats are only necessary if you are starting warm season seeds in a cold area. Not all plants need this and not all places in the home need extra warmth. If you are starting seeds in a very warm room in the house (maybe upstairs – heat rises) you should be fine. If you are using a cool basement, you may need a seed heating mat. However, once the seeds have emerged, they can tolerate cooler temperatures.

TEN: Always label and keep records–within weeks you won’t remember anything. Because the small containers will be close together and under the light, you may want to mark the containers with a black magic marker instead of using plant tags at first.

ELEVEN: What you will see first is not the true leaves but the cotyledons. These once were the halves of the seed. They will look like leaves but soon they will shrivel and die off. Then you should see the first set of true leaves that can begin the photosynthesis process (i.e., make its own food). Decrease watering as you see growth emerge because really the roots are now down deep in the container taking up water so the surface can look a little drier than when you first sowed.

TWELVE: If you planted too many in one container, you can transplant seedlings into other containers after you see this first set of true leaves. Alternatively, you can remove the weakest looking ones with small scissors, just cut across at the base of the soil, do not pull it out.

THIRTEEN: When to start the seed indoors under lights? First determine your average last frost date for your area. Then count backwards the number of weeks given on the seed package. For example, if I use Mother’s Day as my average last frost date then I would start Black Krim tomato seed 6 weeks prior so it would be the last week in March. In that six-week timeframe, I know that probably the last 2 weeks, end of April, beginning of May, I will have moved the seedling to a larger 4-inch pot and place outside on the deck. This period will allow it to harden off.

FOURTEEN: Some seeds have to go through a scarification process where the seed coat either has to be nicked with a file or the seeds have to soak in a container of water for 24 hours before they are sown. For example, soak morning glories in water overnight before you sow them to help the process of breaking down the seed coat and letting the water in. Other seeds need to go through a stratification process of moist, cool temperatures several months before they will germinate. These seeds can be stored in the fridge for a few months before you attempt to sow them. Seed packets should state these requirements.

FIFTEEN: The caveat to #14 is that the seed packet is small and can only offer so much information, so read more information on the company’s website or catalog, or search on the internet, or look in a gardening book in order to have as much knowledge and success as possible for that particular plant.

SIXTEEN: Often there is too much seed in a packet. Don’t think you have to sow all the seed in the packet. In fact, save some in case your initial planting does not work out, or share/swap with friends, or use next year. Most vegetable seed will be viable next year with the exception of onions and leeks.

Good luck!

When Can I Plant My Tomatoes? When Is the Last Spring Frost?

Basil plants for sale in March in Northern Virginia

A lot of us are just itching to start seeds, purchase plants, and start gardening as soon as possible. It is important to know that some plants need warm summer weather, while others thrive in cool spring temperatures. Also, just because it is for sale does not mean that you should sow the seed now or plant the plant in your garden.

First, learn which of your plants/seeds are cool season versus warm season plants. Second, identify your average last frost date so you can figure out your starting time.

Cool season plants thrive in March and April. They can tolerate a cold nip at night. By summer, they may have disappeared, gone to flower, or died back. In the DC metro area, March and April are cool season months and this is when we can plant/sow seeds of spinach, lettuce, cilantro, and kale outside. However, if we were to plant a warm season plant such as tomatoes and basil outside, they would not survive a frost. Warm season plants have to be planted after the danger of frost has passed and the night temperatures are constantly in the mid-fifties. Usually they will do well in the summer, from May until our first autumn frost. You can start the seeds of basil and tomatoes indoors in April under lights where they will stay warm and toasty until you bring them out when it is warmer.

From winter to spring, the chance of frost diminishes. Although some gardeners will plant their warm season plants in mid April, there is still a slight risk of a frost. There is no risk in May and some gardeners use Mother’s Day as a marker for when they can safely plant warm season plants in the garden.

Tomato plants for sale in March in Northern Virginia

Many hardware stores and garden centers will sell plants as early as March, including basil and tomatoes.  People assume that because the plant is there for sale it is okay to plant it in the ground.

Frost is predicted when air temperatures reach 32 degrees. It also may occur when air temperatures are just above freezing due to open exposure to the clear night sky. Frost can be a “light freeze” at 29 to 32 degrees, which usually kills tender plants. Using the 1991-2020 climate normals from the National Oceanic and Atmospheric Administration, the National Gardening Association provides a useful chart outlining probabilities of cold temperatures by dates.

By entering my Northern Virginia zip code, I can see that March 29 is the point where there is a fifty-fifty chance of frost occurring. Some gardeners look for this point to get a head start knowing they may have to cover their plants.  I am more interested in being safe than sorry  — I have no desire to rush out and cover my plants so I am looking for a number lower than 50. Also, the National Gardening Association recommends using 36 degrees as the marker because frost can form at 32 degrees and then fall down into your garden even though it is 36 degrees on the ground. Using this logic, the 50/50 mark is April 9.

On April 10, I have a 10 percent chance of 32 degree temperatures. Ten days later, I have a 10 percent chance of 36 degree temperatures. As time goes by it, the 10 percent chance of frost will diminish to zero (until autumn). Because I am a low risk taker (or possibly too lazy to go outside and cover my plants), I am shooting for less than 10 percent to near zero. Therefore, I can plant basil and tomatoes at the end of April with a slight risk of frost to Mother’s Day when there is no risk.

At this point, when to plant is a personal preference and it also depends on your schedule, your available time. But don’t sow your tomato seeds now and do not plant tomatoes in the garden in March!