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Gardener's checklist for spring

What to do in your garden in the spring

MARCH

Maintenance

  • Let the leaves remain in place on spent daffodils and other spring bulbs; until the foliage dies, it provides nutrients to rebuild the bulb for next year.
  • If you planted a cover crop in fall, chop up the foliage into small pieces and turn under or add the clippings to your compost pile.
  • Replace path mulches that have been washed away by heavy rains.
  • Inspect your irrigation system for leaks and non-functioning emitters and sprayers. Make any needed repairs or changes.

Propagation

  • Start tomato seeds indoors.
  • Sow seeds of fava beans, beets, carrots, leeks, lettuce and other leafy greens, peas, radish, spinach, Swiss chard and turnips.
  • Start begonia tubers indoors in flats.
  • Plant summer-blooming bulbs such as agapanthus, canna, gladiolus, lilies, watsonia and dahlias.

Feed & Fertilize

  • Fertilize roses, citrus and other spring-flowering plants.
  • Fertilize azaleas, camellias and rhododendrons after they have bloomed.
  • Apply compost or a high-nitrogen organic fertilizer to trees, shrubs and perennials, especially those that were planted last fall.

Pests & Weeds

  • Handpick snails and slugs after dark or apply a pet-friendly bait.
  • Be diligent about pulling weeds before they set seed.
  • Apply one to three inches of mulch around plants and on bare areas of your garden to suppress weed germination and growth. Mulch also will retain soil moisture as winter rains subside.

APRIL

Maintenance

  • Troubleshoot your irrigation system for missing or clogged emitters and broken spray heads.
  • Mulch around new plants to suppress weeds and retain moisture.
  • Renew mulch around existing plantings. Keep mulch clear of stems and trunks.
  • Clean winter debris from ponds, fountains and bird baths.

Pests & Weeds

  • Check often for aphids on tender new plant growth. Remove infestations with a hard spray of water or insecticidal soap.
  • Handpick snails and slugs after dark or apply a pet-friendly bait.
  • Be diligent about pulling weeds before they set seed.

Propagation

  • Weather permitting, move frost-tender seedlings and plants outdoors. Harden off transplants before planting by gradually exposing them to outdoor conditions.
  • Sow seeds of summer and fall-blooming annual flowers (cosmos, bachelor buttons, sunflowers, nasturtiums and zinnias) directly in the ground. Keep the seed bed moist.
  • Plant summer bulbs, corms and tubers, such as callas, cannas, dahlias, gladiolus and tuberous begonias.
  • Sow seeds of beets, carrots, lettuce and Swiss chard. Plant potato tubers.
  • Thin raspberry canes.
  • Thin developing fruit such as apples when they reach dime size.

Feed & Fertilize

  • Fertilize spring bulbs after bloom. Remove dead flowers but not the leaves until they wither.
  • Feed lawn areas with a slow-release fertilizer.
  • Fertilize citrus.
  • Apply chelated iron to azaleas, camellias and gardenias if leaves are yellowing between the veins.
  • Renew container plants by adding a slow-release fertilizer or repotting in fresh soil.

MAY

Pests

  • Monitor and control snails, slugs and aphids.

Cutting & Pruning

  • Prune spring-flowering shrubs are they have finished flowering.
  • Pinch back chrysanthemums and annual flowering plants to encourage branching and compact growth.
  • Cut off spent flowers for continued bloom.
  • Prune azaleas, camellias and rhododendrons after they have finished blooming. Feed with a balanced fertilizer formulated for acid-loving plants monthly during the spring and summer.
  • For modern roses, as new growth develops, remove any canes that are growing inward to aid in air circulation. For old garden roses that bloom only once, do the major prune after the bloom cycle is complete. Pick up diseased leaves.
  • Cut roses to bring indoors. As you cut, plunge the stems immediately into a bucket of water.

Propagation

  • Continue to plant seeds of summer and fall-blooming annual flowers or buy cell packs at nurseries.
  • Sow seeds of beans, beets, carrots, corn (early varieties), cucumbers, lettuce, melons, pumpkins, Swiss chard and summer and winter squash.
  • Transplant starts of eggplants, peppers and tomatoes.
  • Plant an herb garden in containers or in a bed near your kitchen. Keep mint in its own pot to control its rampant spread.
  • Fertilize citrus.
  • Continue to thin developing fruit.
  • Repot cymbidiums if they have outgrown their containers or if the planting medium has broken down.


Contributors:

Faith Brown, Marie Narlock, UCCE Marin County Master Gardeners

Resource:
Northern California Gardening: A Month-by-Month Guide by Katherine Grace Endicott