The goal for gardeners who start seeds indoors is to have seedlings that are robust with good color ready to plant outdoors in late May. But often I hear from gardeners that their results are disappointing — the seedlings are lanky, the color poor and the plants appear weak.
So, what went wrong?
Healthy seedlings need water, warmth — generally around 70 degrees — and bright direct light. In our climate, a windowsill generally does not provide enough direct light.
For best results, consider growing vegetables seedlings under fluorescent lighting just an inch or two above the foliage. Move the fluorescent light higher as the plants grow taller. This is easier to do if you use chain link to hang the lighting fixture.
Plants grown in this way need about 16 hours of light. I find it easiest to maintain this schedule by putting the lights on a timer.
The next question is when to plant for best results.
Timing is important
Some crops should have been started already. These include onions, cabbage, cauliflower and Brussels sprouts. Broccoli can be started this week. Eggplant and tomatoes can also be started indoors now to mid-April. Tomatoes and peppers both like additional soil warmth and for this reason, many gardeners start the freshly planted seeds on a radiator or on top of the refrigerator. If you do this, keep an eye that the soil doesn’t dry out completely. Once sprouted move the seedlings under lights.
Save starting cucumbers, peppers, pumpkins, melons, lettuces and herbs such as basil until early May.
Generally you want to allow about 4 inches of space per plant in a flat. If you haven’t grown vegetables before, are planting with a child or if you’ve had trouble separating plants when you are planting outdoors, consider using peat pots as individual containers. It just makes it easier.
When mid to late May arrives, watch the forecast and begin to bringing seedlings outdoors during the day to harden off for a few hours every day for about a week before setting them into the garden. Set them out in a protected space out of the wind.
In our area, gardeners generally plant tomatoes, peppers, eggplants, sweet corn and squash outdoors from late May into the first week of June. There have been frosts into June in our region so keep an eye on the weather forecast. And, if you can, plant on a day that is cloudy so seedlings aren’t stressed by too much sunlight.
There are some seeds that are not worth starting indoors. These include hard-to-transplant vegetables like carrots and parsnips, and also those plants whose individual yield doesn’t warrant starting them indoors, such as beans.
As you plant, place the seedlings gently in the soil and then firmly press the soil around them. Water them by using a diffuser to avoid damaging the seedlings.
Water and Fetilizer tips
Improper watering can kill seedlings. The goal is to keep the soil damp and then let the soil dry out before watering again. Overwatering causes many problems. Never let seedlings sit in water.
Fertilizing can be done once the seedlings have a second set of leaves. This should be done with caution.
For my own plants, I fertilize with a solution that is half the strength recommended on the fertilizer label and I do so about once a week. Never use fertilizer on dry roots as it can do damage. Always water first and then fertilize.
This is a just a general guide. Many seeds have more specific requirements and you will want to read the seed package instructions carefully.
For example, for the highest germination rate annual poppies require a very light dusting of soil to cover. If you planted these seeds too far down, they would never come up.
Some crops like a little cold and can be planted outdoors in early May. These include vegetables such as lettuce, spinach, beans, hardy herbs, carrots, turnips, onions, beets and broccoli, Brussels sprouts and cabbage.
I hope this helps gardeners get their seedlings off to a good start.