September Garden Guide: Soil Prep, Planting, Dividing, and Harvesting

Prepare

Before planting a new lawn or beds, prepare the soil. Dig 10–12 inches deep with a shovel or rotary tiller, then incorporate a 4–6 inch layer of compost or other organic matter. Add a complete fertilizer to lawn areas.

Plant

September begins fall planting season—the ideal time for many plants. Nurseries are well-stocked with trees, shrubs, vines, and groundcovers.

Plant cool-season annuals after mid-month in cooler areas, end of month in warm inland zones (Sunset zones 7–9, 14–17). Keep soil moist; shade new seedlings if hot. Set out calendula, forget-me-nots, Iceland and Shirley poppies, ornamental cabbage and kale, pansies, primrose, stock, sweet peas, violas. In coastal areas, try cineraria, nemesia, schizanthus.

Shop early for the best bulb selection—choose firm bulbs without soft or moldy spots. Plant anemones, crocus, daffodils, Dutch iris, freesias, homeria, hyacinths, ixia, leucojum, lycoris, oxalis, Peruvian scilla, ranunculus, sparaxis, tritonia, tulips, watsonia. (Freesias, homeria, watsonia not hardy in zones 1–2.) In mild climates, chill crocus, hyacinths, tulips in the refrigerator for ~6 weeks before planting, away from produce.

Cool-season greens—arugula, chard, kale, lettuce, mustard—are easy from seed and tastier than store-bought. For variety, try Ornamental Edibles.

Add fall color with asters, chrysanthemums, gaillardia, gloriosa daisy, Japanese anemone, lion's tail, purple coneflower, salvia.

Set out broccoli, cabbage, cauliflower, lettuce, spinach seedlings. Sow beets, carrots, leeks, onions, peas, radishes, turnips.

Maintain

If perennials like agapanthus, candytuft, coreopsis, daylilies, penstemon are overgrown or not flowering well, dig and divide (zones 1–2: early month). Lift clumps with a spading fork, cut into sections with a spade, knife, or pruners. Replant in amended soil; keep moist until roots establish.

Harvest

Continue picking summer tomatoes. Remove finished or diseased plants; compost only healthy material.