Gardening: Cool your desire to dig - most plants need warmer weather before planting

Hold your trowels, folks. It’s still too cold out there to plant many things and the long-range weather forecast seems to be trending colder this year.

There is a long-standing local tradition around here that you shouldn’t plant frost -sensitive plants until after Mother’s Day. Another tradition is that you don’t plant until the snow is off Mica Peak. I can remember scrambling to cover plants several times around that time. Technically our last frost date is around May 15, just a few days after Mother’s Day.

So, what can you plant right now? Cool -season crops like lettuce, carrots, onions, peas, cabbage, broccoli, kale, radishes, beets, potatoes and spinach can be planted if the soil isn’t soggy. It’s been dry enough the last week or so that most soil should be in good shape. These vegetables can take a light frost without damage.

Warm -season crops like tomatoes, peppers, beans, corn, squash, cucumbers, melons, eggplant, basil and tomatillos are sensitive to not only frost but also to cold soil. Cold soil, defined as being 50 degrees and under, can slow root development down significantly enough to stop growth until it warms up later in June. This is why many of our crops planted in the middle of May just sit there. Basil is particularly sensitive to cold soil if it is planted too early. If the soil is too cold, it will turn yellow and usually won’t recover from the condition. I know they have been on the racks at the garden centers for a while, but it isn’t warm enough to plant them out until mid- to late June.

Many plants used in container plantings are frost sensitive so hold off planting pots until after mid-May. The soil in a large pot will be warmer than that of a flower bed, so that will help jump-start the plants when you plant them. It’s still cold to hang fuchsia baskets without protection. If you use time-release fertilizers like Osmocote, be aware that the fertilizer won’t start releasing its nutrients until the soil is close to 70 degrees.

Last, most of the plants we find in our local nurseries now have either been grown in greenhouses or have come from western Oregon nurseries where the spring comes earlier than here. As a result, they are usually well leafed out and that foliage can be frost sensitive. If you buy plants like this, watch the weather closely and put them close to a garage so they can be moved inside or cover them with a tarp should the forecast get frosty. Once they have been our climate for a couple of weeks, they will harden off and be able to handle the weather better.

To protect plants that are already in the ground, keep protective covers handy. Sheets, 5-gallon buckets, floating row cover and a wide range of commercial covers will trap ground heat to keep the plants warm. Remove them in the morning so they don’t overheat.