Preventing Problems When Starting Seeds

The biggest problem for novice growers with growing seeds indoors is starting your seed too soon.

The Intuitive Gardener
Item # 99649 		The Intuitive Gardener: Finding Creative Freedom in the Garden

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  • Topic: Planting Techniques
  • Keywords: seeds, seedlings, spring planting, Planting Techniques
  • Date: January 2002

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Seeds, there are seeds enough which need only be stirred in with the soil where they lie… to bear fruit of a divine flavor.
Henry David Thoreau

Alas, we’re not all so gifted with a hoe as Mr. Thoreau. Starting seeds in the house is a rewarding way to get those fruits of divine flavor, but you’ll have better luck if you’re aware of a few of the difficulties.

The biggest problem for novice growers with growing seeds indoors is starting your seed too soon. Gardeners under the mistaken impression that bigger is better with transplants will have a harder time maintaining plant health, as smaller transplants have an easier time adjusting to the shock of moving.

How do you know when to start your seeds? Find the “days to transplant” time on the seed packet and count backward from the last projected frost date (here in Santa Fe that’s May 15). Add a ten days to two weeks to that figure for hardening off and you’ll have an accurate idea of when to start planting. For example, tomatoes usually take seven weeks to mature into transplant size. Count backwards seven weeks from May 15, add ten days for hardening and you’ll arrive at March 17th.

Other concerns:

Most sickly seedlings are the result of too little light or too much heat. We discussed the light problem in the last issue, so now we’ll talk about temperature. It may seem counter-intuitive, but seedlings actually prefer fluctuating temperatures. Warm days and cool nights is the preferred temperature situation for seedling growth; aim for 70-75 degrees during the day and 50-55 degrees at night.

Another problem that can arise when growing seedlings is a fungal disease known as “damping off”. The disease can prevent seed germination, or can kill seedlings as they are reaching their full development. The best way to avoid this problem is to use sterilized soil, or a soil-less planting medium.

So what is this “hardening off” we referred to earlier? Hardening off is your means of transitioning the seedlings from their cushy indoor life to the harsher realities of life on the outside. To start the process, cut back on your watering for a few days, but don’t let the seedlings wilt. After these few days, begin putting the plants outdoors in a protected area for a few hours then bringing them back inside. Over the next ten days, increase the amount of time they spend outside gradually, at the same time transitioning them to a more exposed area. After they’ve gotten used to several days of 10 to 12 hours outside, leave them outside a full 24 hours for a couple of days, making sure the thermometer doesn’t fall below freezing (for tender plants like basil, the lowest nighttime temperature should be in the low forties).

Even cold hardy plants (like pansies and lettuces) can be damaged by exposure to freezing temperatures before they are hardened off. After properly transitioning them to the outdoors, however, they will be perfectly able to withstand light frosts.