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There’s plenty to do in the March garden as spring arrives

Seeds for summer vegetables, such as tomatoes, zucchini and peppers, are best started indoors in containers.
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It’s been a strange rainfall year. We’ve had big storms alternating with long dry periods. We need to adapt garden practices to keep plants going. Without sufficient rains, plants will face more stress this spring and summer. Be prepared.

Vegetable and annual flower gardens

March kicks off the season for planting vegetable, flower and herb seeds.

Learn — or polish — your seed-starting skills with my Easy Seed Starting Workshop Online. The series walks you through the steps of starting, caring for and transplanting seedlings, along with my tips and tricks for success. For information and registration, visit learn.waterwisegardener.com.

Which seeds can you start now?

  • All the summer veggies such as tomatoes, zucchini, peppers, eggplant, cucumbers, pumpkin, summer squashes and okra. These seeds are best started indoors in containers.
  • Start basil seeds in containers indoors but plant cilantro seeds directly into the garden.
  • Start annual summer flower seeds including sunflowers, marigolds, zinnias, Mexican sunflowers and cosmos, all of which are best to start indoors in containers.
  • Beet, carrot, turnip and radish seeds are best planted directly into the soil.
Carrot seeds are best planted directly into the soil.
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Cut off cover crops at the roots. Let the roots decompose in place. Compost the tops.

Plan to remove cool-season crops as you finish harvesting — broccoli, cauliflower, kohlrabi, lettuce, spinach, etc.

Once your garden beds are empty, prepare them for the next round of crops. Top them off with new soil (not planting mix or potting mix), compost, worm castings and organic vegetable fertilizer.

Test and repair irrigation.

Get, or make, sturdy vegetable supports. My favorite are the DIY cylinders I make from sheets of concrete reinforcing mesh, folded short sides together and secured in place with zip ties. This holds two tomato plants or four cucumber plants or a dozen bean or pea plants. Don’t bother with the conical tomato cages. As plants grow large, they fall over.

Continue to harvest and enjoy the season’s citrus.

Fruiting trees and shrubs

Deciduous fruit trees such as peach, apple, fig and plum should all be in flower and leafing out by now.

To help ensure pollination (and therefore, fruits), devote a nearby bed to plants that attract native and non-native bees, along with other pollinators: rosemary, California lilac, African basil, yarrow, native buckwheat, lavender, catmint and others.

Did you finish spraying stone fruit, apple and pear trees before they began flowering and forming leaves? If not, it’s too late now. Wait until next winter.

Feed all stone fruit, apple and pear trees with a general organic fruit tree fertilizer. Water the fertilizer in, then mulch.

Feed avocado trees with organic avocado food.
Feed avocado trees with organic avocado food.
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Feed citrus, avocado and other subtropical fruit trees with organic citrus and avocado food. Water the fertilizer in, then mulch.

Fig, pomegranate, pineapple guava and loquat trees don’t require fertilizer, but do mulch them thickly.

Plant some lesser-known, easy-to-grow, waterwise fruiting plants:

  • Surinam cherry (Eugenia uniflora) is not a “true” cherry but rather a medium-size evergreen shrub that makes cherry-size, pumpkin-shaped fruits with a hard stone in the center. The fruits ripen through the year, starting out green, then turning yellow, then orange, then ripening to deep red. Fruits are eaten fresh; their flavor is sweet and slightly astringent. Plants thrive in full sun or morning sun and with only periodic irrigation.
  • Ripe cape gooseberry (Physalis peruviana) fruits look like golden tomatillos, but their flavor is sweet with a touch of tartness and very aromatic. These tomato relatives grow as upright, evergreen shrubs that look like giant tomato plants, though more attractive. Ripe fruits are hidden in a brown papery husk — also like tomatillo. Grow in full sun and poor, sandy or other well-draining soil. Use little water along the coast, more inland; no fertilizer. Fruits ripen in late summer. Eat them fresh or cooked.

Ornamental perennials, shrubs, vines and trees

South African bulbs are on show this month — species Gladiolus, starfish flower (Ferraria), bugle lily (Watsonia) and others bloom in full sun. Forest lily (Veltheimia bracteata) blooms best in shade.

Continue planting California natives, including lemonadeberry, oaks, Tecate cypress (excellent screening plant), black sage, white sage, Cleveland sage and monkey flower.

Flush the centers of bromeliad plants in the ground. Turn over potted plants to shake out water, then refill with fresh water. Repot potted plants whose soil level has fallen far below the rim. One local collector recommends a mix that is half seed starter mix, one-quarter coir chunks or chunky orchid bark, and a quarter small lava or pumice, or large perlite.

Start watering plumeria when leaves appear toward the end of the month.

Start fertilizing roses with slow-release fertilizer this month.

Irrigation

When you irrigate, always run the irrigation for the same number of minutes — just much less often in the cooler months than in the warmest months.

Adjust your irrigation for spring. Convert overhead spray systems and outdated point-source drip irrigation to in-line drip. Remember to convert entire zones at once, since different kinds of irrigation operate at different pressures.

Run each irrigation zone and walk the lines looking for leaks, drips, disconnected lines, etc. They are easiest to fix now, while plants are just beginning their spring growth spurt.

More

Now is a good time to refresh your garden's mulch.
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Refresh your garden’s mulch. The goal is a 3- to 4-inch layer over the entire garden, except a patch of bare soil, 5 or 10 feet square, for native, ground-dwelling bees. They are great pollinators and very rarely sting humans.

Pull out weeds by the roots or cut off the top growth with a hoe. Do it as soon as you notice the leaves. Do not let weeds flower. Those flowers contain the seeds for next year’s crop of weeds.

Nan Sterman is a waterwise garden designer and writer and the host of “A Growing Passion” on KPBS television. For more information, visit agrowingpassion.com and waterwisegardener.com.