Question: I have trouble finding plants of the newer award winning varieties of vegetables in local garden stores. I would like to start some of my own plants from seeds. Could you outline some procedures for successfully starting plants inside?
Answer: Vegetable plants can be started in your own home if you have a south facing window. Even if you do have direct sunlight, supplemental artificial light will improve your results. I recommend using LED plant lights which are available online starting at about $25. A heating mat that raises the soil temperature to 70 degrees will speed seed germination (about $30).
I plant seed into flats or small pots using container soil mix. When the outdoor temperature is above 50 degrees, I begin placing my seedling plants outside during the daytime as soon as they have four or five leaves. The alteration of cool, bright outdoor conditions with warmer indoor night temperatures causes plants to grow more compactly. Place plants in the shade for the first few days outside until they become hardened to the dryer outside air. After hardening they should be placed in full sun.
Idaho Falls has an approximate last frost date around May 20. Higher elevations have later last frost dates with comparable later outdoor transplanting dates.
Broccoli, Brussels sprouts, cabbage, cauliflower, mustard, kale, collards, pak choi and kohlrabi are cold tolerant vegetables which can be planted outside as early as late April. They need about six to seven weeks from seed sowing to outside planting. Seed could be started as early as mid-March. Onion and celery are similar but take about eight weeks.
Tomato, pepper and eggplant are frost tender vegetables which should not be planted outside until late May. Tomato and eggplant require about eight weeks to grow a transplantable plant. Peppers require about 10 weeks. A good date for starting tomato and eggplant seed would be about March 20. Peppers should be started about two weeks earlier.
Cucumber, melon, squash and pumpkin seed only require about four weeks from seed planting to outside transplanting. None of these do very well until weather has warmed so I seldom plant them outside before the end of May. Appropriate seed planting time would be about late April.
Seed starting equipment and supplies are usually available at most nurseries and garden stores.
For sources of seed of new award winning varieties go to all-americaselections.org/buy-winners.