Q. When do we in the cold and frozen north here (Utah) start our seedlings? I have a greenhouse at the school I can use until I can get my hubby to honeydew my own greenhouse project. I want to plant cabbages and broccoli and brussel sprouts as well as the warmer weather tomatoes and peppers and such.
A. When to start seedlings is an important question – no matter where you live, and the answer is always the same – “When they won’t freeze!” So when is that? It depends on the plant and your weather. First find out the average last frost date in your local growing micro-climate. The Garden Wizard and Garden Master CD’s do a good job of giving you that for over 3,000 places in the United States. Others will have to ask your local government Ag. agent.
Next, determine the frost tolerance of the plant you’re growing, to know when to transplant into the garden. There are 4 levels of frost tolerance – and I quote from the Mittleider Gardening Course:
1. Hardy plants tolerate frost and cold and can be planted 3 to 6 weeks before the average date of last frost.
2. Moderately-hardy plants handle a certain amount of cold. Plant these 2-3 weeks before the average date of last frost.
3. Cold- and frost-sensitive plants don’t like cold or frost. Plant them on the average day of last frost and protect them against late frost.
4. Frost-intolerant plants will not survive any frost and must be planted 2-3 weeks after the average day of last frost.
With dozens of plant possibilities, I can’t tell you here what each plant’s frost tolerance is, but again the Garden Wizard and the Garden Master CD’s give you all of that in the Review Plants section of the Garden Designer.
And finally, you need to know how long your plant needs to be in the greenhouse before being transplanted, in order to get back to the date on which you plant in the greenhouse. And again I refer you to the Garden Wizard and Garden Master CD’s as the best place to find that information. Remove the uncertainty and confusion in this very important step by looking in the Preview Plants section of the Garden Designer. You will learn the number of days required from planting seeds to transplanting in the garden, for all the common garden vegetables.