Local planting guide · California
zip 90239
Downey is in USDA hardiness zone 10b, with average winter lows of 35°F to 40°F. The local growing season runs roughly 01/09 through 01/05 (~365 days). This zip falls within the California growing region.
- USDA zone
- 10b 35°F to 40°F
- Last spring frost
- 01/09
- First fall frost
- 01/05
- Growing season
- 365 days
- Compatible crops
- 23
- Growing region
- California
Right now in Downey
Week 18 priorities
On the docket: transplant out after last frost · direct sow after last frost. See the full calendar →
Gardening in Downey
Downey's gardening calendar spans nearly 365 days, with minimal frost risk from January through December. The last measurable spring frost arrives around January 9, and the first fall frost doesn't typically return until early January of the following year, making this one of California's most frost-forgiving zones. This extended growing season is a significant advantage, but it masks a more pressing constraint: heat and water management. Summer temperatures regularly exceed 90°F and often push toward 100°F in July and August. Water availability is inconsistent, with drought cycles becoming more pronounced. Chill-hour accumulation falls far too low for many deciduous fruit varieties that thrive in colder climates. Crops like figs, peppers, eggplants, and basil thrive in the warm season, and tomatoes can be planted on multiple schedules throughout the year to capture spring, summer, and fall harvests. Sweet potatoes excel here, as does rosemary, which is essentially a permanent presence. The gardener's advantage in Downey is planting flexibility and year-round productivity, but success requires vigilance about water needs during the critical heat months and careful variety selection for both heat tolerance and dormancy requirements.
Regional context · California
What the California brings to Downey
From cool foggy coast to hot Central Valley to mountain to desert. Mediterranean climate dominates: wet winters, dry summers. The most productive agricultural state in the country, with reach into citrus and olives that exceed the rest of the country.
Common challenges
Issues that most often defeat home gardeners in zone 10b, drawn from the broader USDA zone profile.
- ▸ No winter chill
- ▸ Tropical pest and disease pressure
- ▸ Saltwater intrusion in coastal soils
What defeats new gardeners in Downey
Summer heat in Downey regularly exceeds 95°F, which can cause blossom drop on peppers and eggplants if plants experience water stress simultaneously. This combination of heat and dry air in July and August is the season's critical point. Tomato varieties suited to milder climates often struggle with sun scald and cracking under the intense UV load and diurnal temperature swings. The second significant constraint is winter chill: most apples, pears, and stone fruits require 300 to 800 chill hours (temperatures between 32°F and 45°F), but Downey's mild winters deliver perhaps 50 to 150 hours annually. Gardeners attempting traditional orchard crops without low-chill rootstocks and varieties quickly discover graft failure and sparse fruiting. Powdery mildew pressure increases in humid microclimates, particularly in fall when morning dew mixes with warm afternoon air.
Crops that grow in Downey
23 crops from our catalog match zone 10b, grouped by type.
Tree fruit
12 crops
zone 10b Fig
Ficus carica
zones 7a–10b
zone 10b Lemon
Citrus limon
zones 9a–11b
zone 10b Orange
Citrus sinensis
zones 9a–11b
zone 10b Lime
Citrus aurantiifolia
zones 9b–11b
zone 10b Grapefruit
Citrus paradisi
zones 9a–11b
zone 10b Mango
Mangifera indica
zones 10b–13b
zone 10b Avocado
Persea americana
zones 9b–11b
zone 10b Banana
Musa acuminata
zones 9b–13b
Berries
2 crops
Nuts
1 crop
Vegetables
6 crops
zone 10b Tomato
Solanum lycopersicum
zones 3a–10b
zone 10b Sweet Pepper
Capsicum annuum
zones 4a–10b
zone 10b Hot Pepper
Capsicum species
zones 4a–10b
zone 10b Eggplant
Solanum melongena
zones 5a–10b
zone 10b Sweet Potato
Ipomoea batatas
zones 6a–10b
zone 10b Okra
Abelmoschus esculentus
zones 6a–10b
Herbs
2 crops
Plan the year
Planting calendar for Downey
Year-view of seed starting, transplanting, planting, pruning, fertilizing, harvest, and pest-watch windows tuned to Downey's local frost dates.
Week ? · loading
This week in Downey, CA (zone 10b)
Quiet week in Downey, CA (zone 10b). this week is a good time to step back and plan ahead.
Nothing critical on the calendar this week.
128 bars · 23 crops
Calendar logic combines NOAA frost normals with crop-specific timing data. Local microclimate and weather always overrules the calendar; use this as a starting point.
Top pests for zone 10b
Ranked by how many crops in your zone they affect. Click through for IPM controls and signs to watch for.
Pseudococcidae spp.
Soft white waxy insects that cluster at leaf joints, fruit stems, and root crowns. Honeydew secretion supports sooty mold; root mealybugs cause decline that mimics drought.
Coccoidea spp.
Sap-sucking insects that attach to bark, leaves, and fruit, secreting honeydew that fuels sooty mold. Heavy infestations weaken trees and cause leaf yellowing.
Ceratitis capitata
Quarantine pest in many regions. Adult females puncture ripening fruit to lay eggs; larvae tunnel through the flesh, causing premature drop and rot.
Multiple species (Aphididae)
Small soft-bodied sap-sucking insects that reproduce explosively in spring. Excrete honeydew that supports sooty mold and attracts ants. Transmit viral diseases.
Meloidogyne species
Microscopic soil-dwelling worm that forms galls on roots, reducing vigor and yield.
Multiple species (Aleyrodidae)
Tiny white moth-like flying insects that feed on plant sap and excrete honeydew. Transmit numerous viral diseases including tomato yellow leaf curl virus.
Multiple species (Chrysomelidae)
Tiny black or bronze jumping beetles that put hundreds of small holes in seedling leaves. Most damaging on direct-seeded brassicas and young eggplant.
Anastrepha suspensa
Tropical fruit fly endemic to Florida and the Caribbean. Less aggressive on commercial citrus than Mediterranean fruit fly, but devastating on guava, carambola, and other thin-skinned tropicals.
Top diseases for zone 10b
Ranked by how many crops in your zone they affect. Click through for symptoms, controls, and resistant varieties.
Capnodium spp.
Black fungal coating that grows on honeydew secreted by aphids, scale, mealybugs, and whiteflies. Doesn't infect plant tissue directly but blocks photosynthesis and disfigures fruit.
Colletotrichum gloeosporioides
Most damaging mango disease worldwide. Fungal spores infect blossoms and developing fruit during humid weather, producing black sunken lesions that expand on ripening fruit.
Sclerotium rolfsii
Soil-borne fungal disease most damaging in warm humid Southern conditions. White mycelial fans and small mustard-seed-sized sclerotia at the soil line are diagnostic.
Fusarium oxysporum
Soil-borne fungal disease that plugs vascular tissue and kills affected plants. Persists in soil for many years; impossible to eliminate once established.
Verticillium dahliae
Soil-borne fungal disease similar to fusarium wilt but with broader host range and cooler temperature optimum. Persists in soil for 10+ years.
Candidatus Liberibacter asiaticus
Devastating bacterial disease vectored by the Asian citrus psyllid. Once infected, trees decline progressively over several years and there is no cure. Has destroyed commercial citrus across Florida and threatens production worldwide.
Xanthomonas citri
Bacterial disease producing raised corky lesions on leaves, twigs, and fruit. Spread by wind-driven rain and contaminated tools. Quarantine-regulated in many areas.
Xanthomonas euvesicatoria and X. perforans
Bacterial disease causing leaf spots and fruit blemishes on pepper and tomato. Severe in warm humid weather, transmitted via splashing water and seed.
Companion planting suggestions
Beneficial pairings drawn from companion data, filtered to crops that grow in zone 10b.
- Fig + Rosemary
Rosemary tolerates the dry sites figs prefer and provides aromatic pest deterrence.
- Tomato + Basil
The classic Italian pairing. Basil's volatile oils are reported to repel hornworms and whiteflies, and the two crops share the same warm-season schedule and water needs. Plant basil between tomato cages.
- Sweet Pepper + Basil
Same warm-season culture, same watering schedule. Basil reportedly improves pepper flavor and repels aphids and thrips that are pepper's primary pests.
- Hot Pepper + Basil
Compatible heat-loving culture, similar water needs. Basil interplanted between hot pepper plants supports beneficial insects and reduces aphid pressure.
- Okra + Hot Pepper
Both heat-loving warm-season crops with similar water and fertility needs. Hot pepper at okra's base benefits from the slight afternoon shade in extreme summer heat.
Soil types reference
Soil texture and pH decide what grows easily on your specific lot. Find the closest match below for crop recommendations and amendment guidance.
Practical tips for Downey
Plant tomatoes in two windows: a spring round in late February for an April-June harvest, and a second round in July for a December-January harvest. The mild winter allows the second cycle to extend maturity into cooler weeks, improving flavor compared to summer fruit. Use 30 to 50 percent shade cloth from June through August for heat-sensitive crops like lettuce and basil, which otherwise bolt or scorch; this simple intervention can revive productivity during the hottest weeks. Select low-chill varieties for any stone fruit attempt. Peach and plum varieties bred for zone 9 or warmer regions require only 100 to 300 chill hours, whereas standard orchard varieties demand 600 or more. Rosemary, figs, and peppers require no chill hours and will produce year-round if watered consistently.
Frequently asked questions
- What are the best crops to grow in Downey?
Figs, peppers, eggplants, tomatoes, sweet potatoes, basil, and rosemary are the most reliable producers. These thrive in the warm season and tolerate both the heat and the extended growing window. Avoid traditional chill-hour-dependent fruits like standard apples and pears unless using low-chill rootstocks.
- When should I plant tomatoes in Downey?
Plant tomato transplants in late February for a spring harvest (ready by May-June), and again in July for a fall and winter harvest (ready by December-January). The mild winters allow the second cycle to mature without frost threat, and the cooler months produce better-flavored fruit.
- What's the biggest weather risk for gardeners in Downey?
Summer heat, not frost, is the dominant challenge. Temperatures above 95°F in July and August cause stress on heat-sensitive crops and can trigger blossom drop, fruit cracking, and bolting. Paired with low water availability during peak summer, this is the season requiring the most vigilance.
- Can I grow stone fruits like peaches and plums here?
Yes, but only low-chill varieties. Standard orchard peaches and plums require 600 or more chill hours per season; Downey averages far less. Seek out varieties developed for warm climates (zone 9 or warmer) that need only 100 to 300 chill hours, and verify the exact variety before purchasing.
- How do I keep lettuce and basil from bolting in summer?
Use 30 to 50 percent shade cloth from June through August to reduce heat stress and UV intensity. This simple step can keep cool-season greens and basil productive through the hottest weeks, rather than triggering early flowering and bitterness.
- Is there any frost risk I should plan for?
Downey's last spring frost averages January 9 and first fall frost around January 5, providing year-round frost-free conditions for tender annual crops. Anomalies are rare but possible, so monitor forecasts during late December and early January as a precaution.
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Frost data: NOAA Climate Normals 1991-2020, station USW00003122. Local microclimates can shift these dates by a week or more.
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