Friday, April 9, 2010

Seed warm season crops indoors now

It’s now 7 weeks out from the May 31 traditional Memorial Day transplanting date for warm season crops into the garden. Even though the Denver last frost date is approximately May 10, many gardeners wait until the end of May when weather is more stable to set out tomatoes, peppers, eggplant, squash and more.

If you plan to grow your own transplants, 6 weeks before transplanting is generally sufficient for tomatoes and 8 weeks for peppers. Have the soil in pots warm (70 to 75 degrees F is ideal) and grow in a warm room, not cold basement. One advantage we have in Colorado is many days of bright sunshine so growing in a sunny window is doable even without a greenhouse.

A guide for seeding and transplanting vegetables into the garden based on outdoor soil temperatures follows (see last week for soil temperature details and on-line soil temperature readings link):

Garden soil temperature and planting times
35 degrees F – lettuce and onions
40 degrees F - peas, radish, spinach, cabbage
50 degrees F – tomato, pepper, corn
55 degrees F – beans
60 degrees F – cucumbers, squash, eggplant

Photo credit: Peppers seeded and growing in window - Carl Wilson


  1. I'm new to gardening. I have some good books but lack the geo specific info. This info is very helpful. Keep up the great work!

  2. I need some help figuring out what I did wrong. My tomato seedlings, still inside, were looking a bit wild and starting to lean. I transplanted them into larger containers with potting soil. Directly after re-potting, each plant slowly died. Any ideas on what happened? Thanks.