During March, the day length increases quite dramatically and plants really respond to the extra light. The temperatures are creeping up, but not so dramatically like the light change. Take a walk and notice our native trees and shrubs. They are going crazy with the added light.
I like to divide our garden crops in two categories: cool season and warm season. Let’s plan now for the cool season crops since these can be planted in the early spring, starting in March. The later spring planting (warm season), we can learn about next month for planting in May.
For cool season the earliest crop we plant is peas which I wrote about last month. But also remember to plant onions. Onions are a special case, because they are day length sensitive and need to put in most of their growth before the days get shorter (which happens at the solstice, June 20th). However, onion seeds don’t sprout in cold weather. Gardeners need to start them indoors in February or use onion sets (a bag of small onion bulbs) or starts and plant outside in March.
Here are some cool season crops that local gardeners enjoy. For the lettuce, arugula, spinach, kohlrabi, carrots, parsnips, beets, turnips, broccoli, you can start in Mid March and continue planting them till June. Then I recommend planting these cool season crops again in mid August if they are somewhat shaded and you water them well until the end of our dry summer season. They can provide a lovely harvest in September and October. Some ( like carrots, parsnips, kale) will winter over to give you a delicious early spring harvest too. This stretches your gardening to the year round harvesting, which we are fortunate to have in the Pacific Northwest.
For late spring crops (like beans, corn, squash, cucumbers, and pumpkin) the soil needs to be much warmer. I think of these as being ready to plant after Mother’s Day (which is May 13th this year). We can learn about these crops in this article next month.
Tomatoes, peppers and eggplant are warm season crops that need to be started indoors. The soil isn’t warm enough to sprout tomato or pepper seeds till about June, which doesn’t leave enough time to get the plants to produce their delicious fruits before fall. So, plant the seeds indoors in March, under a grow light or on a warm, south facing window sill where the temperature stays above 65 degrees. The potting mix should be for seed starting, usually with extra peat and well drained. Transplant these little “starts” outdoors in May. Squash and cukes are more delicate to transplant, but with care you can start these indoors in April and transplant in May.
Consider planting your crops in raised beds, by either mounding the beds or building a frame to fill with soil. These raised beds will allow the soil to warm sooner and drain better, which generally allows planting one or two weeks sooner than conventional flat beds. Put the beds in a sunny spot, with good south and east exposure.
What about soil preparation? Spring is the best time to mix in lots of rich compost into your planting beds. Try as much as 6 inches of compost. If you have worm casting compost or a well decomposed leaf mold (compost) or Cedar Grove compost, this may be enough fertility for most of your fruiting type crops (tomatoes, peas, beans, peppers, squash, etc). For your greens (lettuce, broccoli, spinach, chard, mustards, etc.) you may want to add an additional organic nitrogen source like manure, fish fertilizer, alfalfa or cotton seed meal. These are usually sold in packages that have three numbers on the front. Pick an organic fertilizer with the first number, the % nitrogen, being the largest number of the three. I encourage using an organic product because it releases the nitrogen slowly which nourishes the microorganisms that make a healthy soil.
Since much of our rain soaked soil is acidic, you may want to add lime to “sweeten” your soil, especially if you haven’t added it in the last three years. You can purchase an inexpensive bag of garden lime in most nurseries. The brassicas (broccoli, kale, cabbage, choys, etc.) especially like limed soils. Strawberries and potatoes do not.
With all this Spring work, be sure to take some time to do some warm up exercise before gardening, and stop to stretch your stiff and tired muscles regularly. Enjoy the increasingly sunny days!