The Press Democrat, March 01, 2025
Plant potatoes in March using easy fabric pots that can be moved around and take up little space.
We’ll be “springing forward” with daylight savings time March 9 and gaining more hours of sun in our gardens.
After weeks of cleansing rains, perennials are brightly refreshed. New growth is emerging on all plants and erupting from the soil. Everything should be green for St. Patrick’s Day March 17, and the first day of spring will follow closely on March 20. There will be no lack of tasks for the home gardener in the weeks ahead.
St. Patrick’s Day is a good reminder that March is an ideal month to plant potatoes.
Potatoes are well suited for growing in containers and ideal for those of us with limited gardening space. One container option is a grow bag, a fabric pot that is easy to move around for optimal sun. The porous fabric allows the bag to breathe, which can prevent overheating and overwatering.
Start your grow bag with seed potatoes from a nursery that displays a Certified Seed Potato tag, to ensure they are free of disease. Avoid grocery store potatoes; often they are treated with sprout inhibitor. If your seed potatoes are small, you can plant them whole. Cut larger seed potatoes into pieces weighing 1-1/2 to 2 ounces. Make sure each piece has at least one eye. Then, store the freshly cut pieces at room temperature for 1 to 3 days to allow the cut surfaces to dry and form a callus, which decreases rotting.
Potatoes grow best in well-drained loose soil. A good potting soil or a mix of soil and compost works well. Add about 3 to 4 inches of soil to the bottom of each grow bag. Place 4 to 6 small or cut seed potatoes onto the soil. Then cover them with an additional 3 to 4 inches of soil.
Growing potatoes is hilling
When the plants reach about 4 inches tall, add more soil to cover them. This is called “hilling” or “dirting.” Continue hilling as the plants grow until the bag is full. Covering the base of the plants as they grow will prevent the potatoes from exposure to too much sun, which can cause greening, a toxic condition.
Soil in a grow bag or container can dry out quickly. Regularly monitor the moisture content of the soil; it should feel moist, but not soggy. In the hottest part of the summer, you may have to water every day. Note that excessive watering may cause rotting. If the soil is alternately wet and dry, the potatoes may become rough and knobby.
Monitor your plants for pests such as the flea beetle and aphids. Hose aphids off with water or spray with an organic insecticidal soap.
Harvest your potatoes once their vines die, approximately 90 to 120 days after planting. Carefully empty the bag, plants, soil and all, to unearth your potato bounty. Brush off most of the soil, then store the potatoes in a cool, dark place.
Plant your food garden
Are you ready to get your food garden started? March is the time to plant broccoli, cabbage, cauliflower, kohlrabi, beets, carrots, collard greens, bunching onions and kale.
March is also optimal for planting bulbs.
Plant bulbs such as amaryllis, gladioli, dahlias, calla lilies, and daylilies for a pop of color in your summer garden.
Sow wildflower seed now for bloom in summer and on into the fall.
All native wildflowers will eventually self-sow themselves if allowed to go to seed. Good candidates that grow well in Sonoma County include:
Baby blue-eyes, Nemophila menziesii, has light-blue blossoms with white centers that look great in containers. Baby-white eyes, Nemophilamenziesii var. atomaria, has white flowers sprinkled with tiny blue dots. Five spot flowers, maculata, are white with five petals. Each petal has a dark purple spot on its tip.
Blue field or birds-eye gilia, Gilia tricolor, is endemic to Sonoma County and does well in dry ground. The fragrant blue, lavender, violet and pink flowers attract hummingbirds and butterflies. They grow to 8 inches tall and reach peak bloom in March to April.
California poppies, Eschscholzia californica, are yellow-orange flowers that reseed prolifically. They grow from 2 inches to 2 feet tall from February through September. Ragged plants can be pruned back to near ground level after the seed pods dry. Collect the dry seeds and sow them in other areas of your garden.
Sonoma Clarkia, Clarkia gracilis ssp. sonomensis, has a brilliant pink flower with a magenta spot on the base of each petal. It grows up to 12 inches tall and is notorious for its drooping buds. Red ribbons, Clarkia concinna, grow well in the shade and up to 18 inches tall. Elegant clarkia, unguiculata, with diamond-shaped petals, grows 2 feet tall. Since all Clarkias bloom from April to July, their common name is farewell-to-spring.
Chinese houses, or pagodas, Collinsia heterophylla, tolerate shade. These delightful flowers emerge in colors of white, rose and purple. Blooms are tiered in whorls with a lilac or white upper lip and a rose-purple or violet lower lip. They bloom from February to April and grow up to 10 inches tall. They make a good bulb cover.
Fertilize your garden
Feed roses and other flowering perennials that are emerging from winter dormancy with an organic fertilizer at bud break and once a month thereafter.
Fertilize fruit trees. Applying 2 inches of aged compost is ideal. Alternatively, apply a 7-1-7 organic fertilizer in the spring. If mature fruit trees did not put out sufficient shoot growth and/or good fruit set last year, the University of California Agriculture and Natural Resources recommends applying half of a nitrogen fertilizer in March or April and the second half of the treatment in July or August. Always follow label directions when applying any form of fertilizer.
When fertilizing, feed the soil, not the plant. Plants get their nutrients from the minerals and organic matter in the soil or from added fertilizers, amendments and compost. Always read labels and follow manufacturers’ instructions.
Repot and feed houseplants.
The growing season for your houseplants begins in early spring.
Contributors to this week’s column were Diane Judd and Debbie Westrick. The UC Master Gardener Program of Sonoma County sonomamg.ucanr.edu/ provides environmentally sustainable, science-based horticultural information to Sonoma County home gardeners. Send your gardening questions to scmgpd@gmail.com. You will receive answers to your questions either in this newspaper or from our Information Desk. You can contact the Information Desk directly at 707-565-2608 or mgsonoma@ucanr.edu.
Photo: Master Gardener Debbie Westrick