When to Plant Brassicas in Santa Cruz County | Planting Calendar
When to Plant Brassicas in Santa Cruz County: A Season-by-Season Schedule
The best time to plant most brassicas in Santa Cruz County is late summer through early fall, with transplants going into the ground from mid-August through mid-September for a harvest that spans October through February. According to UC ANR's planting guides for coastal California, fall-planted brassicas consistently outperform spring plantings because the gradual cooling temperatures align perfectly with the crops' needs during head and sprout formation. That said, our mild coastal climate supports two full brassica seasons and, for some crops, nearly year-round production. This calendar covers every major brassica crop with specific timing for Santa Cruz County's distinct microclimates. For crop-specific growing details, see our guides to growing broccoli, cauliflower, cabbage, and Brussels sprouts in Santa Cruz County.
Timing brassica plantings correctly is the single most important factor in your success. Plant too early in spring and a late frost can stunt transplants, causing buttoning in cauliflower or bolting in napa cabbage. Plant too late in fall and shortening days and cooling soil temperatures slow growth before heads can form. Our coastal fog and moderate temperatures give us wider planting windows than most of California, but precision still pays off.
How Do Santa Cruz County's Microclimates Affect Planting Dates?
Santa Cruz County is not one uniform climate zone. The differences between our coastal flats, inland valleys, and mountain areas significantly affect brassica planting timing.
Coastal Zone (Santa Cruz, Capitola, Aptos, Watsonville)
- USDA Zone: 10a to 10b (average minimum 30 to 40 degrees F)
- Summer highs: Typically 65 to 75 degrees F, with significant fog influence
- Winter lows: Rarely below 28 degrees F
- Brassica advantage: The longest and most forgiving planting windows. Some brassicas can be grown nearly year-round. Fog belt areas may support summer broccoli production.
- Challenge: Downy mildew risk is highest in the fog belt due to persistent moisture.
San Lorenzo Valley (Felton, Ben Lomond, Boulder Creek, Scotts Valley)
- USDA Zone: 9b to 10a (average minimum 25 to 35 degrees F)
- Summer highs: 75 to 90 degrees F, with less fog influence
- Winter lows: Can dip to 22 to 25 degrees F
- Brassica advantage: Cooler nights promote excellent fall and winter brassica flavor. Good microclimates along the valley floor.
- Challenge: More temperature extremes than the coast. Summer heat can cause bolting in spring-planted brassicas. Winter cold can damage unprotected crops.
- Timing adjustment: Plant spring brassicas 1 to 2 weeks later than coastal dates (to avoid late frost) and fall brassicas 1 to 2 weeks earlier (to ensure establishment before cold weather).
Summit and Mountain Areas (Summit Road, Loma Prieta, upper SLV)
- USDA Zone: 9a to 9b (average minimum 20 to 30 degrees F)
- Summer highs: 70 to 85 degrees F
- Winter lows: Can reach the teens
- Brassica advantage: Cool summers are excellent for brassica growing during months when lower elevations are warmer.
- Challenge: Hard freezes in winter can damage or kill brassica crops. Shorter frost-free season.
- Timing adjustment: Plant spring brassicas 2 to 3 weeks later than coastal dates. Harvest fall brassicas before hard freezes (mid-November typically), or use heavy row cover/frost blankets for protection.
What Is the Complete Spring Brassica Planting Schedule?
Spring planting targets a harvest before summer warmth arrives (though in our fog belt, "summer warmth" is relative). The key is to start early enough that plants have time to form heads but not so early that young transplants are damaged by cold.
Indoor Seed Starting (Spring Season)
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | Late Dec to mid-Jan | Early to mid-Jan | Mid to late Jan |
| Cauliflower | Late Dec to mid-Jan | Early to mid-Jan | Mid to late Jan |
| Cabbage (green/red) | Late Dec to mid-Jan | Early to mid-Jan | Mid to late Jan |
| Cabbage (napa) | Not recommended for spring | Not recommended | Not recommended |
| Brussels sprouts | March to mid-April | March to mid-April | April |
| Kale | Jan to Feb | Jan to Feb | Feb to March |
| Collards | Jan to Feb | Jan to Feb | Feb to March |
| Kohlrabi | Feb to March | Feb to March | March |
Seed starting conditions: According to the UC IPM cole crops guide, maintain soil temperature of 70 to 75 degrees F for germination (use a heat mat if needed). Brassica seeds typically germinate in 5 to 10 days. Grow seedlings under strong light (grow lights or bright south-facing window) to prevent legginess. Transplants are ready when they have 4 to 6 true leaves, typically 4 to 6 weeks after sowing.
Transplanting Outdoors (Spring Season)
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | Mid-Feb to mid-March | Late Feb to late March | Mid-March to early April |
| Cauliflower | Late Feb to mid-March | Early to late March | Mid-March to early April |
| Cabbage (green/red) | Mid-Feb to mid-March | Late Feb to late March | Mid-March to early April |
| Brussels sprouts | Late April to May | Early to mid-May | Mid to late May |
| Kale | March to April | March to April | April |
| Collards | March to April | March to April | April |
| Kohlrabi | March to April | March to April | April |
Transplanting tips: Harden off seedlings for 5 to 7 days before transplanting by gradually exposing them to outdoor conditions (start with a few hours of filtered light, increasing to full days). Plant on a cloudy day or in the evening to reduce transplant shock. Water immediately after transplanting and apply mulch.
Direct Sowing Outdoors (Spring Season)
Some brassicas grow well from direct-sown seed, avoiding the transplanting step:
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli rabe | Feb to March | March | March to April |
| Turnip greens | Feb to April | March to April | April |
| Mustard greens | Feb to March | March | March to April |
| Kohlrabi | March to April | March to April | April |
| Kale | March to April | March to April | April to May |
Direct sowing conditions: Soil temperature should be at least 45 degrees F for germination (60 to 75 degrees is ideal). In spring, coastal soils may still be cool, so be patient. Sow seeds 1/4 to 1/2 inch deep. Keep soil consistently moist until germination. Thin seedlings to proper spacing when they have 3 to 4 true leaves.
Spring Harvest Windows
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | April to June (+ side shoots) | May to June | May to July |
| Cauliflower | May to June | May to June | June to July |
| Cabbage | May to June | May to July | June to July |
| Broccoli rabe | April to May | May to June | May to June |
| Turnip greens | April to June | May to June | May to July |
| Mustard greens | April to May | May to June | May to June |
| Kohlrabi | May to June | May to June | June to July |
| Kale | Ongoing | Ongoing | May to ongoing |
| Collards | Ongoing | Ongoing | May to ongoing |
What Is the Complete Fall Brassica Planting Schedule?
Fall is the premier brassica season in Santa Cruz County. The combination of warm soil for establishment, gradually cooling temperatures for head formation, and our mild winters for extended harvest creates ideal conditions that few other regions can match.
Indoor Seed Starting (Fall Season)
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | Late June to mid-July | Mid-June to early July | Early to mid-June |
| Cauliflower | Late June to mid-July | Mid-June to early July | Early to mid-June |
| Cabbage (green/red) | Late June to July | Mid-June to mid-July | Early June to early July |
| Cabbage (napa) | Late July to early Aug | Mid to late July | Mid-July |
| Brussels sprouts | March to April (same as spring, for fall harvest) | March to April | March to April |
| Kale | July to Aug | July to Aug | July |
| Collards | July to Aug | July to Aug | July |
| Kohlrabi | Aug | July to Aug | July |
Note on Brussels sprouts timing: Brussels sprouts are unique among fall-harvested brassicas because their long growing season (90 to 120 days) means they are actually started in spring and grown through summer for a fall and winter harvest. They are not started in midsummer like other fall brassicas.
Transplanting Outdoors (Fall Season)
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | Mid-Aug to mid-Sept | Early Aug to early Sept | Late July to late Aug |
| Cauliflower | Mid-Aug to early Sept | Early to mid-Aug | Late July to mid-Aug |
| Cabbage (green/red) | Aug to mid-Sept | Aug to early Sept | Late July to late Aug |
| Cabbage (napa) | Late Aug to early Sept | Mid to late Aug | Mid-Aug |
| Brussels sprouts | Late April to May | Early to mid-May | Mid-May |
| Kale | Aug to Sept | Aug to Sept | Aug |
| Collards | Aug to Sept | Aug to Sept | Aug |
| Kohlrabi | Sept | Aug to Sept | Aug |
Fall transplanting tips: Summer soil is warm, which promotes rapid root establishment, but the heat can stress young transplants. Water deeply at transplanting and provide temporary shade (shade cloth or a shingle propped on the south side) for the first 3 to 5 days during hot weather. Mulch immediately to keep roots cool.
Direct Sowing Outdoors (Fall Season)
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli rabe | Sept to Oct | Sept | Aug to Sept |
| Turnip greens | Aug to Oct | Aug to Sept | Aug |
| Mustard greens | Sept to Oct | Sept | Aug to Sept |
| Kohlrabi | Aug to Sept | Aug | Aug |
| Kale | Aug to Sept | Aug to Sept | Aug |
Fall/Winter Harvest Windows
| Crop | Coastal Zone | San Lorenzo Valley | Summit |
|---|---|---|---|
| Broccoli | Oct to Jan (+ side shoots) | Oct to Dec | Sept to Nov |
| Cauliflower | Nov to Jan | Oct to Dec | Sept to Nov |
| Cabbage (green/red) | Oct to Feb | Oct to Jan | Sept to Nov |
| Cabbage (napa) | Oct to Nov | Oct to Nov | Sept to Oct |
| Brussels sprouts | Sept to Feb | Sept to Jan | Sept to Nov |
| Broccoli rabe | Nov to Jan | Oct to Nov | Oct |
| Turnip greens | Oct to Jan | Oct to Dec | Sept to Nov |
| Mustard greens | Nov to Jan | Oct to Dec | Oct to Nov |
| Kohlrabi | Nov to Dec | Oct to Nov | Oct |
| Kale | Ongoing through winter | Ongoing with protection | Oct to March (with protection) |
| Collards | Ongoing through winter | Ongoing with protection | Oct to March (with protection) |
Why Is Fall Actually Better Than Spring for Most Brassicas?
The UC ANR California Master Gardener Handbook and UC Cooperative Extension publications consistently note that fall-planted brassicas outperform spring plantings in coastal California. Here is why:
Temperature Trajectory
Spring-planted brassicas establish during cool weather and must form heads as temperatures are rising. This creates a race against time: if the plant does not finish heading before warm weather arrives, quality suffers (bolting in broccoli, buttoning in cauliflower, loose heads in cabbage).
Fall-planted brassicas do the opposite. They establish during warm weather (which promotes vigorous vegetative growth) and form heads as temperatures gradually cool. This cooling trajectory is exactly what brassicas want during the critical heading phase. The result is denser, sweeter heads with better texture.
Day Length Effects
Shortening days in fall trigger many brassicas to shift from vegetative growth (leaf production) to reproductive development (heading). This natural signal, combined with cooling temperatures, produces a coordinated transition to heading that spring's lengthening days do not provide as cleanly.
Pest Pressure
Many brassica pests (flea beetles, cabbage worms, aphids) are most active in spring and summer. Fall-planted brassicas establish during peak pest season but mature during the cooler months when pest pressure declines. This often means less pest damage on the harvested product, especially for heading crops.
Soil Moisture
Fall plantings benefit from the return of natural rainfall in October and November, reducing irrigation needs during the critical final growth phase. Spring plantings may need supplemental irrigation right through harvest.
The Exception: Brussels Sprouts
Brussels sprouts are started in spring specifically because they need the long, warm growing season (90 to 120 days) for vegetative development. They are the one brassica where spring planting is essential, but even Brussels sprouts are harvested in fall and winter, taking advantage of the cooling temperatures for sprout maturation.
How Do You Succession Plant Brassicas for Continuous Harvest?
Succession planting means starting new batches of the same crop at regular intervals so that plants mature at different times, extending the harvest window.
Succession Planting by Crop
Broccoli: Plant a new batch every 2 to 3 weeks during the planting window. With three spring successions (mid-Feb, early March, mid-March) and three fall successions (mid-Aug, early Sept, mid-Sept), you can harvest broccoli from April through January, with a gap only in late summer.
Cabbage: Stagger plantings every 3 weeks. Use early-maturing varieties (Early Jersey Wakefield, Golden Acre) for the first succession and longer-season varieties (Red Acre, Late Flat Dutch) for later ones. This provides fresh heads over several months.
Cauliflower: Succession plant every 2 to 3 weeks with the same variety, or plant early-maturing and late-maturing varieties at the same time. Because each cauliflower plant produces only one head, succession planting is especially important for this crop.
Broccoli rabe, mustard greens, turnip greens: These fast-growing greens are ideal for succession planting. Sow a new 4-foot row every 2 weeks during the spring and fall windows for a continuous supply.
Kale and collards: These crops produce for so long from a single planting that succession planting is less necessary. One spring planting and one fall planting of each usually provides year-round production.
Practical Succession Planting Schedule (Coastal Zone)
Here is a concrete succession plan for a family that wants continuous brassica harvests:
Late December: Start broccoli and cauliflower seeds indoors (Spring Batch 1). Mid-January: Start broccoli and cauliflower seeds indoors (Spring Batch 2). Start cabbage seeds. Mid-February: Transplant Spring Batch 1 broccoli and cauliflower. Direct-sow broccoli rabe, turnip greens. Early March: Transplant Spring Batch 2 broccoli and cauliflower. Transplant cabbage. Direct-sow mustard greens. Mid-March: Start Brussels sprouts seeds indoors. Direct-sow more broccoli rabe. Late April to May: Transplant Brussels sprouts. Late June: Start broccoli, cauliflower, and cabbage seeds indoors (Fall Batch 1). Mid-July: Start Fall Batch 2 seeds indoors. Start napa cabbage seeds. Start kale and collard seeds for fall. Mid-August: Transplant Fall Batch 1. Transplant kale and collards. Early September: Transplant Fall Batch 2, napa cabbage. Direct-sow broccoli rabe, turnip greens, mustard greens. Late September: Direct-sow more broccoli rabe and mustard greens. October onward: Harvest fall brassicas as they mature. Brussels sprouts ready by late September.
What About Winter and Year-Round Planting?
In Santa Cruz County's mildest coastal areas, some brassicas can be planted in winter for early spring harvest:
October transplant (Coastal Zone only): Broccoli, cabbage, and kale transplanted in October can overwinter and produce heads in February through March. This works best in the most frost-free areas (West Cliff, Live Oak, Capitola). Row covers or frost blankets provide insurance against the occasional freeze.
November through December direct sowing (Coastal Zone): Broccoli rabe, turnip greens, and mustard greens can be direct-sown in late fall for a winter harvest. Growth will be slow during the shortest days but picks up in January as days lengthen.
Year-round crops: Kale and collards truly grow year-round in the coastal zone. A single plant can produce harvestable leaves for 12 months or more. In the San Lorenzo Valley and summit areas, winter production requires frost protection (row covers, cold frames).
How Do You Decide Between Starting Seeds Indoors and Direct Sowing?
Start Indoors (Recommended for Most Heading Brassicas)
Advantages: - Controlled environment ensures good germination. - You gain 4 to 6 weeks of growing time. - Transplants are less vulnerable to pests (flea beetles, slugs) than tiny seedlings. - Easier to manage spacing and timing.
Best for: Broccoli, cauliflower, cabbage, Brussels sprouts, kale (heading types), and collards.
Direct Sow
Advantages: - No transplant shock. - Simpler and less labor-intensive. - Some crops (broccoli rabe, turnips) do not transplant well.
Best for: Broccoli rabe, turnip greens, mustard greens, mizuna, tatsoi, kohlrabi, and kale (for baby greens).
UC Master Gardener training materials note that "most brassica crops benefit from indoor seed starting and transplanting" because the controlled start produces stockier, more uniform plants that establish more quickly in the garden.
Frequently Asked Questions
What is the single most important brassica to plant this fall?
If you can only plant one brassica this fall, make it broccoli. It is the most reliable and productive brassica for Santa Cruz County, producing a main head plus weeks of side shoots from a single plant. Fall-planted broccoli (transplanted mid-August to mid-September) will reward you with harvests from October through January or later. Varieties like Waltham 29 and De Cicco are especially generous with side shoot production.
I missed the fall planting window. Can I still plant brassicas?
In the coastal zone, yes. You can transplant broccoli, cabbage, and kale through October and even into early November, though yields will be smaller and harvests later than optimal. Row covers help protect late plantings from cold and pests. In the San Lorenzo Valley and summit areas, late planting (after mid-October) is risky because cold weather and short days will slow growth significantly.
How cold is too cold for brassicas in Santa Cruz County?
Most mature brassicas tolerate temperatures down to about 26 to 28 degrees F without damage. Brussels sprouts and kale are the hardiest, surviving into the low 20s. Cauliflower is the least cold-tolerant, with curd damage possible below 25 degrees. Young transplants are more sensitive than established plants. In Santa Cruz County, temperatures below 25 degrees are rare in the coastal zone but can occur in the San Lorenzo Valley and summit areas during December and January cold snaps. For a deeper look at local freeze dates and how they affect planting, see Understanding Frost Dates in Santa Cruz County.
Can I plant brassicas in the same bed every year?
It is not recommended. Planting brassicas in the same soil year after year increases the risk of clubroot, black rot, and other soil-borne diseases, and depletes specific nutrients that brassicas consume heavily (particularly nitrogen and calcium). Rotate brassicas to a different bed every 3 to 4 years. If you have limited space, at minimum skip one year between brassica plantings in the same bed and amend the soil heavily with compost.
Do brassicas need full sun in Santa Cruz County?
Brassicas perform best with 6 to 8 hours of direct sunlight. However, in the fog belt, our filtered marine layer often provides diffused light rather than full sun, and brassicas still grow well in these conditions. In the San Lorenzo Valley, afternoon shade from redwoods can actually benefit brassicas by keeping temperatures cooler during warm periods. Avoid deep shade (fewer than 4 hours of light), which produces leggy, weak plants with small heads.
When should I order brassica seeds for fall planting?
Order seeds by June at the latest. Popular varieties can sell out by midsummer, especially from specialty seed companies. If you are growing transplants from seed, you need seeds in hand by late June (coastal zone) or mid-June (SLV/summit) to start them on schedule. Reliable seed sources for coastal California brassica varieties include Johnny's Selected Seeds, Territorial Seed Company, Renee's Garden (based in Felton, right here in Santa Cruz County), and Kitazawa Seed Company for Asian brassicas.
Timing is everything with brassicas, and Santa Cruz County's coastal climate gives us more latitude than most regions. Two full planting seasons, mild winters for extended harvest, and fog-belt microclimates that support nearly year-round production of some crops make this one of the best places in California (and the country) to grow the brassica family. Use this calendar as your guide, adjust for your specific microclimate, and keep records of what works in your garden. Over time, you will fine-tune a brassica planting schedule that keeps your kitchen stocked from January through December.
For more growing guides and California garden resources, visit Your Garden Toolkit.
