Nascent roots and stems
Displace freshly warming earth
Chill nights slow their birth
Citrus pruning should not be started until after March 15th, but now is the time to seriously inspect for mummies. Mummies are those shriveled up, fuzzy gray oranges that house millions of fungal spores. When removing mummies, try to disturb them as little as possible, or cover them with a plastic bag before removing them from the tree. If a citrus tree shows signs of chlorosis (yellowing) on older leaves, it may indicate a nitrogen deficiency. Interveinal (between leaf veins) chlorosis usually means a micronutrient, such as iron or manganese, is needed. Our soil tends to be very low on iron, but you can’t know for sure without a soil test. After the danger of frost has (nearly) completely passed, on March 15th, give citrus trees a good pruning. Just be sure to keep a look out for nests. It’s that time of year!
Walking on wet ground causes soil compaction. This is especially true for the Bay Area's heavy clay soil. Rather than walking on wet soil, stay on paths, install stepping stones, or just wait for it to dry. Compacted soil is particularly difficult for young roots to move through, and it can cause drainage problems.
Winter and spring moisture provide the perfect habitat for many pathogens. You can prevent diseases, such as fireblight on apple, pears, quince, and loquat, with fixed copper sprays. You can also reduce the chance of powdery mildew on grapes by applying sulfur at this time.
Feed young trees
As young trees continue putting out new roots, shoots, and leaves, they will benefit from being fed in March. Check the specific species of tree for more information on how much fertilizer should be provided.
Another common March task is to inspect and repair sprinklers, drip systems, and water collection systems. How do you know if you have an irrigation leak? It can be difficult to spot, especially if it is small. The most common indication is an area that gets and stays wet longer than everywhere else. Sprinklers should be aimed so that they do not hit tree trunks, walkways, driveways, or sidewalks. The former can cause fungal diseases and the latter creates wasteful urban drool.
March is also a good time to prune out dead branches and twigs from fruit and nut trees and ornamental trees and shrubs. It is easier to see the structure of each plant before it is covered with leaves.
If your roses haven’t already started producing leaves and blooms the way mine have, March is a good time to prune them for better airflow and structure. You can also start feeding roses in March, and you may need to spray for black spot. Black spot is a fungal disease that loves moisture. As dew collects on rose leaves, the fungus reproduces astronomically. You can use neem oil or a fungicide.
March is an excellent time to start planting your summer garden. In the Bay Area, you can still direct sow many cool weather crops, such as beets, broccoli, cabbage, carrots, cauliflower, chard, lettuces, spinach, bok choy, fennel, kale, mustard greens, parsnips, and turnips. And it's not too late to install that asparagus bed! March is an excellent time to add cilantro, dill, and parsley to your garden, but wait for warmer temperatures before planting basil and peppers. Potatoes and radishes can be planted now, and you can start tomatoes and peppers in pots, but only if you can protect them from nighttime cold. Otherwise, wait for April, when soil temperatures rise and the serious planting begins! As you dedicate seeds to a specific location, make sure to read the seed package labels for things like mature size, thinning requirements, and sunlight needs, and be sure to use plant markers!
Slugs & snails
Our warming temperatures and moisture work together to create the perfect habitat for slugs and snails. These mollusks can devastate seedlings in a single night, so be prepared. I urge you to follow the link to slugs and snails to learn more about the specific ingredients in different bait products. They are not created equally, and some can harm pets. Choose accordingly.
If you have not conducted a soil test recently, now is the time. Find out what is in your soil before you start adding plants. This will help avoid nutrient imbalances that can wreak havoc on plant health.
Walk through your garden in March and you are sure to see weeds coming up in every location imaginable (and a few unimaginable places!). Your Number One March garden task is weeding. Since some weeds can go to seed in as little as a week, now is the time to cut them off at ground level with a hoe. Wait until later in the season and thousands of seeds will already be sown. Healthy weeds make great additions to the compost pile. Personally, I feed them to my chickens.
Enjoy the early blossoms!