Thursday, February 19, 2009

Countdown to Seed Starting

Although it is only February, folks are getting antsy about planting. I recently spoke to a person who had 50 lbs of seed potatoes scheduled for March delivery. When we had finished talking, that had changed to 25 lbs of spuds and a later delivery date.

This reminded me that lots of folks have questions about when to plant various crops. Part of the problem is that books often give a very wide range of dates or otherwise mislead readers. Books rarely get specific enough for local conditions.

So, where do we start? In Bucks County, the last spring frost usually occurs about mid May. Actually two key dates are useful. The median frost free date (50-50 chance of a frost) is about May 1 and the 90 % frost free date is about May 20, northern Bucks dates being later than southern Bucks. These dates are very useful when determining when to start transplants indoors.

Check out Penn State’s handy guide to seed starting for common veg crops. It details how long certain species should be grown indoors prior to transplanting and when they can be planted outside . Let’s take tomato as an example. If I am conservative and don’t want to risk frost injury, I’ll plan to set out plants on May 15. It takes tomato seed a week to germinate and I will grow it for 5 weeks before transplanting outside. So, working backwards six weeks (1 + 5) from May 15, I see that seeding tomato on April 1 will put me in the ballpark. If I am a bit of a risk taker, perhaps I’ll start them in late March and hope for a warming trend in early May. You get the idea.

Of course, some vegetable crops are seeded directly into the garden. Here you need to know their tolerance for cold. Peas tolerate cold well and can be direct seeded very early (late March/ early April)while plants in the squash family must wait until June.

There are other factors besides temperature involved. Some garden soil remains wet late into the spring. So, although those potatoes will tolerate cool soil… cool and wet soil can spell trouble. Waiting a week or two can be the difference between success and failure.

For a complete set of common vegetable crop fact sheets see this site. They contain information on planting dates as well as varieties, fertility, common pests, harvest suggestions and more.

Thanks to Kansas State University for the image of Broomcorn seed

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