By Sue Hurley, U. C. Master Gardener
Don't be fooled by Mother Nature. She can wipe out your newly planted vegetable seedlings in one cold snap.
April brings warm days along with the typical gardener's urge to buy and plant some tomatoes and peppers for summer eating. The nurseries tempt us with their healthy seedlings, and it is hard to resist. But a cautious person will remember that the soil temperature should be at least 65ºF in the morning before planting these heat-loving vegetables.
Last year, I bought a soil thermometer. I was amazed how cold my soil was and how long it took it to reach the desired planting range of 65ºF to 75ºF.
April soil can range from soggy to dry. Avoid digging in wet soil, which can damage soil structure. Seeds don't germinate well in overly wet soil, but seedlings need moderately moist soil to thrive. Grab a handful of your soil and try to form it into a ball. If it holds together loosely, you're ready to plant. If it clumps, it's too wet.
When you do plant your seedlings, watch them with vigilance. Newly planted seedlings are tender and at risk of wilting, freezing or sunburning between morning and night, depending upon the weather and soil conditions. An experienced gardener has a frost-protection plan that can be but into place at a moment's notice. A simple plastic sheet can be spread over tender plants to save them from certain death. Make sure the sheet doesn't touch the plants and remove it in the morning once the air warms. Don't forget to keep your new plants moist.
As the soil warms, you can plant seedlings of tomato, pepper, eggplant, basil, sage and thyme. Beets, carrots, chard, chives, endive, parsley, radishes and turnips are hardy and their seeds can be planted directly in the soil. Wait to plant heat-loving plants until the weather stabilizes or you may be planting them more than once.
Some of the drought-tolerant flowering plants available now include aquilegia, armeria, candytuft, dianthus, gaillardia, helianthus, lavender, penstemon and various veronicas. Penstemon is one of my favorites. Besides being hardy, it blooms in a range of colors.
If you can't wait for the soil temperature to rise, you can plant alyssum, calendulas, forget-me-nots and violas (pansies). Violas are not only prolific bloomers but also look fantastic from a distance if planted in masses.
April is your last chance to plant flowering bulbs such as amaryllis, caladium, callas, dahlias, gladiolus, tigridia and tuberous begonias. The spring bulbs have just about finished blooming now, but leave the foliage to mature naturally. The foliage gathers nutrients for next year's blooms. You might want to feed the foliage once just after the blooms have faded with 10-10-10 fertilizer.
I know that it is an all-out race to keep after those sprouting and thriving weeds. But do keep them, as well as the never-ending snail and slug population, in check. Some weed varieties reappear almost overnight if you don't pull the complete root system out. The Master Gardener office has free handouts on these and other topics.
One of your most important maintenance jobs is to check your irrigation system. For drip irrigation, a one-gallon emitter should fill a 35-millimeter film can in 35 seconds. Replace clogged emitters and those that do not work. Make sure the emitters are not too close to plant stems or tree trunks.
Early spring is the time to propagate new plants from cuttings. It is easy to do. At virtually no cost, you can increase your stock and replace old, leggy plants with new ones. Plus you can share your successes with friends.