Courtesy of Annie’s Annuals & Perennials

Warm weather is right around the corner. Here’s what to do in your garden now.

Contributors: Johanna Silver, Marcia Tatroe,
 Jim McCausland, Scott Calhoun, and Kathleen N. Brenzel. Compiled by Nicole Clausing  –  Updated March 18, 2021

All Regions 

Prep

Test the viability of vegetable seeds left over from last year by putting a few on a damp paper towel. Fold the towel over the seeds and place in a resealable plastic bag, marking the bag with the name of the vegetable. Store at room temperature and check in a week to see if the seeds have germinated. If not, it’s time to order replacement seed. 

If you’re redesigning your garden, indicate where new trees, shrubs, or garden beds will go by marking their locations on the ground with aerosol garden chalk, which comes in many colors. It’s like spray paint, but temporary, and available at any garden center. 

Maintain

Turn on drip irrigation systems and repair any leaks. Flush sediment from filters and check screens for algae; clean with a small brush if necessary. 

To create reusable plant markers, dip the tops of wooden stakes in chalkboard paint (available in craft stores). Use them now to mark the spots where you’ve sown seeds, and in the spring to identify herbs in your garden. 

Protect

Water the garden before forecasted frosts—plants are less susceptible to damage when the soil is moist. 

Check plants for early signs of infestation by insects such as aphids (look for distorted new growth and tiny, often green or black insects) and spittlebugs (look for white foam on the stems). Blast them off with a hose.

Succulents contain lots of water in their leaves, making them useful for firescaping (landscaping to prevent or minimize fire damage). 

Sharpen shovels to keep them working effectively. Using a large file, with the shovel facing up, rub along the shovel’s bottom edge at a 45° angle, filing from the left side to the tip; repeat on the right side. With a clean cloth, apply a small amount of mineral oil to the newly sharpened edge to prevent rust; wipe off before using. 

When buying bare-root fruits, vegetables, and ornamentals, keep roots moist from the time you leave the nursery until you plant them in your garden. 

Harvest

Citrus ripens only while on the tree, so sample fruit to gauge sweetness before harvesting a mass quantity. 

Northern California 

Plant

Start tomato seeds indoors for planting outside in late March or early April. 

Continue to sow seeds of cool-season vegetables such as broccoli, chard, and lettuce. 

After the last frost, plant herbs such as basil, chives, cilantro, parsley, and tarragon in a sunny location outdoors. Consider putting herbs in containers close to the kitchen for easy snipping. 

Add spring-flowering shrubs such as daphne, quince, rhododendron, and viburnum to your garden now for color in spring. 

Maintain

Feed annuals, perennials, and trees with an all-purpose fertilizer. 

Bent, blue, fescue, rye, and other grasses begin their spring growth spurts now. Feed with a high-nitrogen lawn fertilizer according to label directions. 

Protect

Keep apples worm-free by setting codling moth traps high in trees before flower petals fall. 

Harvest

Pick the outer leaves of collards, kale, mizuna, and mustard to add to winter soups. Snip young, tender leaves from the center of each plant to eat raw or braise lightly. 

Pick asparagus from year-old plants when spears reach 5 to 8 inches long. To keep plants healthy and productive, harvest for only 4 to 6 weeks, or until thinner spears appear. Then mulch with compost and allow plants to grow. After the third year, extend the harvest period to 8 to 10 weeks. 

Northwest

Plant

Start seeds of warm-season vegetables like cucumbers, eggplant, melons, peppers, squash, and tomatoes indoors this month so they’ll be well established in time for May planting outdoors (June in cold country). 

Sow beets, carrots, onions, peas, radishes, and spinach directly in the garden. Raised beds are optimal for early sowing: They drain well, and their soil warms up quickly. 

Spring-flowering trees (cherries, magnolias, plums) and shrubs (Forsythia, winter hazel, witch hazel) can go into the ground now. Don’t forget pussy willows and ornamental hazelnuts, whose catkins put on a show early in the season. 

Maintain

Rains reveal the low, flood-prone spots of a garden. That’s where to plant moisture lovers, such as gunnera, Japanese iris, and sedge. 

Snip dead tops off last year’s perennials and grasses to make room for new spring growth. 

Build wooden raised beds now to give veggies an early start. Ideal dimensions are 4 by 8 feet, with 10-to-12-inch-high sides. 

Rinse off houseplants in a shower and prune faded foliage. When you see the season’s first new growth, fertilize lightly with a plant food formulated for indoor plants. 

Protect

If you have woody plants that are troubled with insects and mites, spray them with horticultural oil to smother overwintering pests. 

Handpick slugs from your plants or set out bait for them, since they can mow down seedlings before you even realize the plants have germinated. We like to use Sluggo, a biodegradable slug and snail bait. 

Rinse houseplants in a lukewarm shower to remove dust, which harbors pests. Sponge off dust on indoor plants that are too big to move, making sure to dust the undersides of the leaves. If you like glossy leaves, spray with a leaf-shine product. Make dusting your plants part of your cleaning routine. 

Southern California 

Prep

Order seeds, such as bean, corn, eggplant, pepper, pumpkin, tomato, and zucchini, for spring and summer vegetable gardens. 

Plant

Sow beets, carrots, collard greens, lettuces, peas, potatoes, radishes, and turnips. 

Attract beneficial insects by planting the nectar- and pollen-bearing plants they love, such as aster, coreopsis, cosmos, feverfew, scabiosa, and yarrow. 

Plant seeds of summer flowers such as gaillardia, marigold, Mexican hat, and zinnia in pots on sunny windowsills. 

Maintain

Set traps now before gophers become a problem: They are more active when the soil loosens after winter rains. 

Pinch off strawberry blooms through May to ensure large, sweet berries instead of small, tart ones. 

When early apples, pears, and stone fruit are 1⁄2-inch in diameter, thin fruit to 4 to 6 inches apart. 

Give mature avocado trees their first of two feedings for the year. Each tree needs 2 pounds of actual nitrogen per year, so check the fertilizer label for percentages of NPK (nitrogen, phosphorus, and potassium). Feed the entire root zone (without disturbing the tree’s shallow feeder roots) and water. 

Protect

To foil tomato psyllids, enclose plants of eggplant, pepper, potato, tomatillo, and tomato inside square tomato cages covered with floating row covers. 

Prevent mildew by planting disease-resistant varieties of cucumber, melon, and squash from seed. To keep birds from dining on freshly planted bean and corn seeds, cover them with upside-down berry baskets or bird netting. Once the seedlings are 4 inches tall, birds lose interest. 

Southwest 

Plant

For pops of color, plant flowers such as alyssum, calendula, canna, gladiolus, pansy, and petunia. 

Sow seeds of chives, cilantro, dill, and parsley. Plant marjoram, oregano, rosemary, and sage. 

Create a moon garden (one with white blooms that catch a glow at dusk or in moonlight). Consider night-blooming hesperaloe (H. nocturna), white tufted evening primrose (Oenothera caespitosa), and desert snow-in-summer (Plumbago scandens). 

In the low desert, plant broccoli, cauliflower, English peas, onions, and other cold-tolerant vegetables. At higher elevations, sow wildflower seeds now for blooms later in the season. Try blue flax (Linum lewisii), Rocky Mountain penstemon, and sand penstemon (P. ambiguus). 

Maintain

Cut back ornamental grasses such as blue grama, deer grass, regal mist muhly, and sideoats grama to about 1 foot tall. New growth will rapidly obscure the remaining brushlike tuft. 

Before the end of February, fertilize citrus using a plant food formulated for citrus and avocado. 

In low-desert locations, separate dense clusters of succulents such as agave, Echeveria, Graptopetalum, and yucca. Let the pups’ roots scab over in the shade for a few days, then replant. 

Protect

As insects become active, treat agaves with a systemic insecticide containing imidacloprid to deter agave snoutnose weevils, which can kill the plants. 

Fight insect infestations by introducing their natural predators. Try ladybird beetles or green lacewings for aphids; for desert species such as yuccas that are prone to spider mite, get the spider mite destroyer (Stethorus punctillum). Follow label directions before releasing them in the evening hours. 

Harvest

Pick grapefruit, kumquats, oranges, and tangelos. Once they’re plump and fully colored, taste one fruit—if it’s sweet, the rest of the tree should be ripe for picking. 

Mountain

Plant

Plant strawberries in a sunny spot, keeping plants well watered and covered with a frost blanket for the first few weeks. 

As soon as soil thaws, plant brilliant orange- or red-blossomed crocosmia, lavender-flowered gayfeather (Liatris spicata), and fragrant lily-of-the-valley. All thrive in irrigated beds where they can naturalize and spread. 

Fill sunny windowsills with potted English primroses in shades of blue, brown, orange, peach, red, white, and yellow. When they stop flowering, plant them in the garden in sun or part shade. They’ll bloom again in the fall. 

Start seeds of broccoli, cabbage, cauliflower, and kohlrabi indoors in a sunny window or under grow lights to have seedlings ready to go in the ground in late April or early May. 

Maintain

Prep vegetable beds by tilling in 3 to 4 inches of compost, leaving soil clods large to help trap moisture until planting time. 

To prevent soil compaction, clean up beds while the ground is still frozen. 

Keep pine trees dense and compact by cutting or snapping in half new shoots while they are still supple and before they produce needles. 

Protect

Sparrows and house finches tear up crocus blossoms. Place foil pinwheels every few feet among the flowers to discourage the birds. 

Shovel snow onto garden beds to add insulation, which helps prevent temperature swings in the soil. 


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