March Gardening Topics

Frost in March?

Frost can still occur in March and it is especially hard on tender new growth. First and last frost dates for Santa Clara County are November 15 and March 15. Always wait to prune out frost damage until after all threat of frost is past. You will often be surprised at how much has survived. Early pruning can also lead to further dieback along stems and branches.

Seeding for your Vegetable Garden

Starting your own seedlings is fun, easy and can please your taste buds too. You can select vegetables that are grown for a particular flavor such as heirloom varieties, many of which are not offered in garden centers. Planning a garden now allows you to consider all the factors needed for success, including location, soil conditions, and how they affect plant selections.

There are two ways to start your seeds: direct sow straight into your garden or indoor sow. Direct sowing is easy for some plants such as peas, corn, beans, and squash. Tomatoes, eggplants and peppers are best started indoors and then planted in the ground after they are developed and sturdy. Three factors influence germination: water, temperature, and light. Information found on the seed packages will show which conditions are best for germination.

Peppers need high soil temperature (70°—78° F) for optimal germination. This can be attained indoors using a heating pad.

Weed Management

"One-year seeding makes seven years weeding." Can that really be true? Yes and the reason lies in the genetics of seeds. They are programmed to sprout under a variety of cultural conditions. Most sprout under normal conditions. However, some will remain dormant, sometimes for years, before germinating under unusual conditions such as during a drought or after a long winter or fire. This mechanism helps ensure the survival of the species. It certainly ensures that you need to get out and pull your weeds before they go to seed!

Right now is the best time to weed because the weeds are small and have not gone to seed and the soil is moist so you can get the whole root system. The most effective way to remove weeds is by hoeing and hand pulling.

Rather than applying pre-emergent herbicides, read Weed Management in Landscapes, Pest Note 7441. You will also find information about specific weeds, including dandelions, creeping wood sorrel, purslane, annual bluegrass, field bindweed, spotted spurge and Bermuda grass.

Excellent information is also available in the Weed Science chapter of the California Master Gardeners Handbook, a book available for purchase at the UCCE Santa Clara County Master Gardener Program office by calling 408-282-3105.

Save Money on Irrigation

Consider various forms of irrigation conversion! Irrigation systems, especially drip and micro-sprinklers, have drastically improved over the last few years. For example, there are kits that convert pop-up sprinkler heads to low-flow systems. The conversion kits include a pressure regulator to control changes in pressure and a filter to improve water quality. Water usage is reduced through better water management; control of distribution and less loss from evaporation. Other advantages include water is placed more accurately and efficiently in the root zone; it is applied at a slow rate that reduces loss from runoff; and dry soil between plants allows you to work in the garden between irrigating. The key to success is watering long enough to supply adequate water to the root zone. As with any irrigation system, they are efficient only when regularly monitored for proper watering conditions.

Citrus Housekeping

Do not start working on your citrus trees until at least March 15 and after new growth has appeared. They are particularly subject to frost damage when leafing out so pruning before the last frost could increase the amount of dieback of your plant. Compared to many ornamental trees, citrus generally need less pruning. Judicious pruning should include removal of dead, diseased or broken branches and some thinning if the tree gets very dense.

Yellowing of leaves (chlorosis) may indicate a nutrient deficiency. Yellowing of older leaves can be an indication that the tree needs more nitrogen and inter-veinal (between leaf veins) chlorosis usually indicates a micronutrient deficiency such as iron or manganese Until the soil warms in the spring, the roots may not find the nutrients available. Foliar application of chelated micronutrients allows absorption anytime of year. A great new resource for the home orchard grower is Home Orchard: Growing Your Own Deciduous Fruit and Nut Trees.