Our first planting season of the year begins at the end of January when soil temperatures warm to 55 degrees and above. We have a much earlier start to spring planting than other climate zones and can plant seeds and transplants of cool-weather crops such as lettuces, spinach, broccoli and carrots as well as spring-blooming annuals including pansies, stock and Iceland poppies in what is late winter in other areas. This early cooler growing season only lasts until temperatures are consistently in the mid to high 70’s or the first hot spell (usually in late April) and overlaps with the first plantings of seeds and transplants of summer vegetables and annuals in late March and early April. Many eager Central Valley gardeners will be squeezing in their precious tomato transplants alongside mature chard and ripening beets in mid-March.
During the next couple of weeks amend the soil in your planting beds, especially where you plan to put in root crops including beets, carrots, radishes and turnips. The dense heavy clay soil that is prevalent in many Central Valley gardens does not allow for good root development or good drainage. To lighten the soil and improve drainage, lay down a two to three-inch layer of compost or humus, top the compost with shovel loads of gypsum or gypsite, then turn the amendments into the soil to a depth of about 12 inches. Adding compost or humus to sandy soil will improve water and nutrient retention.
Local nurseries are often the best places to find seeds and transplants of cool-season plants that are most suitable for our climate. Like many avid gardeners, I pour over seed catalogs when the weather keeps me indoors to search for unusual and new varieties that may not yet be available at nurseries and garden centers. When buying seeds, seed tapes and transplants from nurseries, garden centers or seed catalogs, check labels and catalog descriptions for growing zones (8 and 9 in the valley; zone 7 in the foothills) and for days to maturity. With a short spring growing season, you’ll want to find varieties that mature in less than 70 days.
Our short rainy season coincides with the spring planting season, but we cannot rely on rainfall to sufficiently irrigate young plants with small root systems. Most cool season plants need more water than warm season plants. Luckily, irrigation systems have improved mightily the last few years. Check out drip tapes that can be buried underground and are great for irrigating root crops right at the roots. I also have been pleased with the results with the drip emitters that irrigate root zones with an umbrella-like shower, spreading water evenly over a wider area and requiring fewer emitters.
After having recommended lower number granular fertilizers for years with few choices available from smaller companies, it’s gratifying to see so many big name fertilizer companies bringing a wide range of fertilizer types onto the market. In well-amended soils, seeds and transplants benefit from the large amounts of micro-organisms and micro-nutrients available to plants’ roots and need less fertilization, less often. Wait two weeks after putting in transplants and wait until new sprouts are an inch or two high to give a first feeding of a tablespoon or two of a lower-number fertilizer.
Send Elinor Teague plant questions at firstname.lastname@example.org.