Extension Service Garden Hints

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Soil temperature is key to the timing of veggie planting in spring

CORVALLIS - It is time to start thinking about choosing and buying this year's "cool season" vegetable seeds and plants.

These include arugula, fava beans, beets, broccoli, Brussels sprouts, cabbage, carrots, cauliflower, kale, leeks, lettuce, many of the oriental greens, onions, parsnips, peas, radishes, spinach Swiss chard and turnips.

A good way to determine when to plant your vegetable seed is to determine whether a crop is a "cool season" or "warm season crop," suggested Bill Mansour, vegetable crops specialist with the Oregon State University Extension Service. Cool season crops that will germinate in coolest soils include arugula, fava beans, kale, lettuce, pac choi, parsnips, peas, radicchio, radish and spinach. These seeds will germinate at temperatures as low as 40 degrees.

When soil temperature is above 50 degrees, cool season vegetables such as Chinese cabbage, leeks, onions, Swiss chard, and turnips can be planted. When the soil warms to 60 degrees, some warm season and many cool season vegetables can be sown, including beans, beets, broccoli, Brussels sprouts, cabbage, carrots and cauliflower. Beans will not tolerate any frost and may have to be planted again if the temperature goes below freezing. Wait until the soil warms to above 70 degrees to plant warm season vegetables such as tomatoes, eggplants, peppers, cucumbers, squash, corn and melons.

Below are some hints to help home gardeners successfully grow their early season vegetable seeds:

• Wait to plant until the soil reaches the proper temperature for a specific crop.
• Buy cold tolerant or short season varieties.
• Warm the soil with a plastic mulch, cloche, Wall-o'-Water, spun fiber or fabric "floating" row cover or cold frame.
• Prepare well aerated soil with plenty of organic matter for a seed bed.

By: Carol Savonen
Source: Bill Mansour

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