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Starting Seeds Indoors

Dundee Fact Sheets

Starting Seeds Indoors                           Print This Sheet


Many flowers and vegetables can be started indoors from seed. By having sturdy seedlings to transplant later, you will have flowers and vegetables earlier in the summer.

See the Dundee Fact Sheet called “Spring Garden Guide” for information about when to start seeds. Seed packets will also have helpful information.

There are many different seed starting containers you can use, including small plastic pots, peat pots, seed trays, and Jiffy-7 pellets. Whatever containers you choose, make sure they are very clean, have good drainage, and are deep enough to accommodate growing roots.

Use lightweight soil mixes specifically recommended for seed starting. Heavier soils will not provide the necessary drainage and air circulation. Wet the soil before you plant with a mixture of water and

fungicide to help prevent disease. Adding a layer of milled sphagnum peat over the top of the soil will also help prevent a disease called “damping off” which causes seedlings to keel over.

Follow planting directions on the seed packet, especially concerning how much to cover the seeds. As a general rule, don’t cover more than 2 times the diameter of the seed. Don’t crowd the seeds. After planting, mist the surface with warm water. Use a humidity dome to conserve moisture. Remove the dome, as soon
as the seeds germinate.

In order to germinate, seeds need adequate moisture and heat (about 70-75 degrees). Most seeds also need good light. Although the soil should never dry out, it should also not be overly wet. Misting is a good way to ensure adequate moisture without flooding. Heat can be provided by using heat cables or by placing the flats in a warm area of the house. Light is provided by a window (no direct sun) or by using artificial lights. Fluorescent tubes, or grow lights, work well if they are left on for about 18 hours a day. Keep the lights about 3”-5” away until seeds germinate. Once the seedlings appear, move the lights so they are 5”-8” away. If you are using a window to provide light, turn the containers a little every day so the plants won’t grow to one side.

If you see green or white fuzz on the soil, there is either too much moisture or not enough air circulation.

Once the plants are up and growing well, they should be thinned. To avoid damaging the roots of the remaining plants, use scissors to cut out excess plants.

If you started seeds in seeding flats, you will have to transplant the seedlings into individual pots as soon as they develop their second set of true leaves (the first leaves are called “seed leaves” and they look different).

A few days before transplanting, slice a square around the plant with a sharp knife. This will prune the root ball and get the plant used to being on its own. Use a forked stick or a pencil to carefully uproot the plant at transplanting time. Handle the plant by a leaf, not by its fragile stem.

As the time nears for putting the plants outside, gradually harden them off by placing the pots outside in a shady, out-of-the-wind spot for a few hours every day, if it’s warm enough. If possible, transplant outside on a cloudy, windless day.


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