August is the month of “transition”: peak-season harvests are still arriving in full force, but autumn work is already starting too. Seedlings raised in June go outside now, and for many early crops it’s time to save seed.
Transplanting and sowing autumn crops
- 🥦 Cabbage, broccoli, kale: seedlings started in June go outside now — choose a cloudy day
- 🥗 Spinach, radish, lettuce: autumn sowing continues, choose a cooler, shadier bed
- 🧄 Winter garlic: for some varieties, soil prep and planting can start from end of month
Prime seed-saving time
August is peak season for saving seed from early crops.
- 🫘 Beans, peas: leave a few pods on the plant to fully mature and dry
- 🥬 Bolted lettuce: once the seed stalks dry, the seed is easy to collect
- 📦 Store collected seed dry, cool, dark, labelled — this is the foundation of a home seed bank, giving you free seed year after year
August tasks overview
| Plant | Task | Note |
|---|---|---|
| Cabbage, broccoli, kale | Transplant outdoors | Seedlings started in June go out now |
| Spinach, radish, lettuce | Outdoor sowing | Continuing autumn sowing, choose a cooler spot |
| Winter garlic | Soil preparation | Plantable from end of month for some varieties |
| Beans, peas (early varieties) | Seed saving | Leave a few pods to fully mature for seed |
| Tomato, pepper, courgette | Continuous harvest | Still peak season, but watch for slowing growth |
| Green manure crops | Sow into freed beds | E.g. phacelia, mustard — fast soil regeneration |
Continuous harvest and plant condition
- 🍅 Tomato, pepper, courgette: continuous harvest, but growth may naturally slow toward end of August
- 🌧️ Warm, humid weather raises the risk of fungal diseases — ventilate, avoid watering foliage
- 🏖️ If going on holiday, arrange for watering: drip irrigation or a neighbour
Summary
August is both the “peak of harvest” and “preparing for autumn” month. Brassicas started in June go outside now, you can collect seed from early beans and peas, and freed-up beds can be put to work with green manure or a second sowing.
❓ Frequently Asked Questions
Why are cabbage-family seedlings started in June transplanted out precisely in August? These plants need a long, cooling autumn to form heads, and there’s exactly enough time left before frost for a seedling transplanted now to mature — earlier it would struggle in summer heat, later it wouldn’t have enough time to develop.
Why leave some bean/pea pods to fully mature and dry on the plant instead of picking them green? The seed only becomes mature and viable once it dries completely inside the pod on the plant — a seed picked green hasn’t yet developed the reserve nutrients and protective seed coat it needs, so it wouldn’t germinate next year.
Why should collected seeds be stored dry, cool, and dark? Moisture and heat trigger the seed’s metabolism, and light breaks down compounds that regulate germination — dry, cold, dark storage keeps the seed in a dormant state, preserving its viability for years.
Why avoid overhead watering in warm, humid weather? Wet leaf surfaces combined with warmth create ideal conditions for fungal disease spores to germinate — if water reaches only the soil around the base, the leaves stay dry and spores can’t take hold and spread.