Now
38°C · Clear
Today
39° / 26°
Soil 6 cm
34°C
First frost
~98 days (Dec 15)
Gardening in San Antonio
AI field guide · refreshed weeklySan Antonio Gardening: Early Fall Planting Window Opens
You're in zone 9a with 98 days until your first frost (mid-December). Soil at 35°C (95°F) is still hot but cooling; seeds will germinate reliably now. Your 302 frost-free days mean you can plant cool-season crops through mid-September and harvest well into winter. Spring frost risk ends mid-February, so fall is your main planting season.
Sow outdoors now
Lettuce & Leafy Greens
Direct sow 'Buttercrunch', 'Red Sails', or 'Jericho' lettuce, plus spinach and arugula. Germinate in 7–10 days at current soil temps; thin seedlings and harvest leaves in 30–40 days.
Broccoli & Cabbage
Sow 'Arcadia' broccoli and 'Early Jersey Wakefield' cabbage directly or transplant seedlings started indoors 4–6 weeks ago. Mature in 50–70 days before December frost.
Radishes
Plant 'Cherry Belle' or 'French Breakfast' radishes; they'll mature in 25–30 days and tolerate the heat better than other brassicas.
Peas
Sow 'Sugar Snap' or 'Snow Pea' varieties directly; they need cool nights (below 21°C/70°F) to set pods well, so timing is tight—plant this week before heat lingers.
Carrots
Direct sow 'Nantes' or 'Chantenay' varieties; germination is slow (14–21 days) in warm soil, so keep seed bed moist and mulch lightly to cool it.
Start indoors now
Tomatoes (Fall crop)
Start 'Surefire' or 'Phoenix' determinate varieties indoors now for transplant in 6–8 weeks; they'll fruit before frost and handle San Antonio's heat better than spring varieties.
Peppers
Start 'Jalapeño M' or 'Thai Hot' from seed; they germinate slowly (10–14 days at 24–27°C) but will produce through winter if transplanted by late October.
Herbs (Cilantro & Parsley)
Start seeds indoors in trays; cilantro especially bolts in heat but thrives in fall and winter once established. Transplant seedlings outdoors in 3–4 weeks.
Harvest now
Summer Squash & Zucchini
Pick daily; plants slow production as nights cool but will keep yielding through September if watered deeply.
Okra
Harvest pods when 7–10 cm (3–4 in) long; plants are still productive but will decline as temperatures drop below 27°C (80°F) at night.
Basil
Cut stems regularly to delay flowering; pinch off flower buds to extend harvest another 2–3 weeks before frost kills the plant.
Eggplant
Pick fruit at full color; production slows but continues through October if plants stay hydrated and mulched.
Tasks this week
- Water deeply 2–3 times this week—forecast shows minimal rain and soil is still hot; mulch beds to retain moisture and cool roots.
- Deadhead spent flowers on summer annuals (zinnias, marigolds) to redirect energy into new blooms before frost.
- Prepare beds for fall crops: amend with 5 cm (2 in) compost and work in a balanced fertilizer (5–5–5 or 10–10–10).
- Set up shade cloth (30–50%) over newly sown seeds and transplants for the next 2–3 weeks to ease the heat shock.
- Scout for spider mites and whiteflies on peppers, eggplant, and tomatoes; spray with neem oil at dusk if populations spike.
Watch out for
- Heat stress on transplants: even cool-season crops need afternoon shade and consistent moisture until established. Wilting signals root damage.
- Powdery mildew on squash and okra: humidity is low now, but watch for it as fall rains arrive; thin foliage and avoid overhead watering.
- Grasshoppers and katydids are active in September heat; hand-pick or use row covers on young brassica seedlings.
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