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Vegetable Transplants Timetable

Curtis Swift, Ph.D., Colorado State University Extension

Vegetables transplants should be started in the home, greenhouse or hot bed based on the recommended age the transplant should be when it is planted to the garden and the date of the average last spring freeze. Since transplants are more susceptible to cold than plants direct seeded to the garden, transplants are usually planted after the average last spring freeze. Once you know that date, count back the number of weeks indicated on the following table and start your transplants accordingly.

The specific cultivar selected for use as a transplant should be based in part on the length of the growing season and the relative maturity rate of that cultivar. Cultivars that develop slowly (require a long growing season) would not the proper choice for an area with a short growing season.

Before you set your transplants into the garden they may need to be hardened off for the conditions they are going to be exposed to. To learn more about Hardening your transplants check out my fact sheet.

Vegetable Soil Temperature for seed Germination 1 Time Required
for growing Plants
for Field Transplanting 4
Optimum Range
(oF)		 Day 2
(oF) 		Night
(oF)		 Time
(weeks)
Asparagus 60 - 85 70 - 80 65 - 70 8 - 10
Broccoli 68 - 86 60 - 70 50 - 60 5 - 7
Brussel Sprouts 75 60 - 70 50 - 60 5 - 7
Cabbage 45 - 95 60 - 70 50 - 60 5 - 7
Cauliflower 45 - 85 60 - 70 50 - 60 5 - 7
Celery 60 - 70 65 - 75 60 - 65 10 - 12
Corn, Sweet 60 - 95 70 - 75 60 - 65 3 - 4
Cucumber 60 - 95 70 - 75 60 - 65 3 - 4
Eggplant 75 - 90 70 - 80 65 - 70 6 - 8
Lettuce 40 - 80 55 - 65 50 - 55 5 - 7
Muskmelon 75 - 95 70 - 75 60 - 65 3 - 4
Okra 85 - 95 3 70 - 75 65 - 70 4 - 6
Onion 50 - 95 60 - 65 55 - 60 10 - 12
Pepper 65 - 95 65 - 75 60 - 65 6 - 8
Squash / Pumpkin 70 - 95 70 - 75 60 - 65 3 - 4
Tomato 60 - 85 65 - 75 60 - 65 5 - 7
Watermelon 70 - 95 70 - 80 65 - 70 3 - 4
s

1. Adjust temperatures slightly to alter growth rates.
2. Select the lower temperature on cloudy days. Daily fluctuations to 60 o or lower at night is essential for some vegetables.
3. A hard seed coat prevents good germination. Treatment of seeds with concentrated sulfuric acid for 2-3 hours or soaking seeds in hot water (113 o F) for 1 1/2 hours improves germination.
4. Transplants older than recommended suffer more shock when transplanted to the garden and often produce less of a crop over the course of the growing season than transplants of the proper size and age.

reference gif References used:
Lorenz, O.A., and D.N. Maynard. 1988. Knott's Handbook for Vegetable Growers, Third Edition. Wiley-Interscience Publications
Splittstoesser, W.E. 1984. Vegetable Growing Handbook, Second Edition. AVI Publlishing Company, Inc.
Yamaguchi, M. 1983. World Vegetables; Principles, Production and Nutritive Values. Van Nostrand Reinhold Company.