Sixteen Indoor 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 seed starting 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 (May 9) 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!

4 responses to “Sixteen Indoor Seed Starting Tips

  1. Modern insulated windows filter out more sunlight than old fashioned glass windows. It works well for the home interior, but not so much for plants.

  2. There’s a lot of good basic info here = a real service! 1.Yeah, I used to make my own starting & potting soils for different kinds of plants; I’m more grown up now and I think the industry has gotten smarter about bagging ready-made mixtures for us($). 2.I’m a believer in watering seeds with warm water by spritzer & gently from below yet I might be kidding myself.

  3. Amazing Blog… many things to learn. thanks for sharing

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