What to Plant in August: A South African Flower Seed Guide

August 10, 2026

Diamond Field Blooms Sweet Pea Seeds growing on a wooden trellis in golden light

August in South Africa is a gardener's secret weapon. We're still in the tail end of winter, but the days are getting longer and the soil is beginning to warm — making this the ideal time to get your flower seeds into trays and prepare for the spring burst ahead.

Here's your guide to what to sow this August so you're ready to hit the ground running when spring arrives in September.

Why August Is the Sweet Spot for Seed Sowing

Late winter in South Africa (especially in the Western Cape, Highveld, and KwaZulu-Natal) brings longer days and gradually warming temperatures. Many flower seeds are surprisingly cold-tolerant and can be started in trays now, giving them a head start before the warmer spring weather arrives. Starting now means your seedlings will be strong and ready to transplant when spring arrives in September.

Top Flower Seeds to Sow in August

Sweet Peas (Lathyrus odoratus) — August is actually the last call for sweet peas in warmer regions. They love cool conditions and will reward you with fragrant, delicate blooms in early spring. Sow directly into the ground or in deep pots.
Pansies & Violas — These cold-hardy favourites thrive in late winter. Sow in trays now for cheerful colour through August and September.
Snapdragons (Antirrhinum) — Cool-season bloomers that do beautifully when started in trays in August. Transplant into beds once they're established.
Stocks (Matthiola incana) — Wonderfully fragrant and perfectly suited to cool weather. Sow in trays in August for spring blooms.
Larkspur (Consolida) — A cottage garden classic that actually prefers to be sown in cool conditions. Direct sow into prepared beds in August.
Echinacea (Coneflower) — A hardy perennial worth starting from seed now. Slower to establish but stunning and long-lived — a worthwhile investment for your garden.
Alyssum — Low-growing, honey-scented, and cold-tolerant. Sow in trays or directly into borders for a soft, frothy edge to beds.

What to Save for September

Warm-season flowers like sunflowers, zinnias, and cosmos need warmer soil temperatures to thrive. Hold off on these until September when spring is properly underway — they'll germinate faster and grow stronger for the wait.

Tips for Successful August Sowing

Use quality seed-raising mix — avoid heavy garden soil in trays, which can compact and prevent germination.
Water gently — use a fine rose or misting bottle to avoid disturbing seeds.
Keep trays in a sheltered spot — a sunny windowsill or a protected patio works well. Avoid frost pockets.
Label everything — seedlings all look the same at first!
Thin seedlings early — overcrowding leads to weak, leggy plants.