California’s diverse microclimates mean your planting calendar for amaranth depends heavily on your specific region. Knowing the best time to plant amaranth in california is the single most important step for a successful harvest, whether you’re growing it for its nutritious leaves or striking seed heads.
Amaranth is a warm-season crop that thrives in heat. It hates frost and struggles in cold, wet soil. In California, you have a long growing window, but timing it wrong can lead to stunted plants or no seeds at all. Let’s break it down by region and method.
Understanding Amaranth’s Temperature Needs
Amaranth seeds need warm soil to germinate. The ideal soil temperature is above 65°F (18°C), with optimal germination around 70-85°F. Air temperatures should stay consistently above 50°F at night.
If you plant too early, seeds rot. If you plant too late, the plants might not mature before the first fall frost. In most of California, you have a generous window, but coastal fog and mountain cold can throw off your timing.
Best Time To Plant Amaranth In California
The exact best time to plant amaranth in california falls between late April and early July for most inland and valley areas. For coastal regions, you can start as early as March. For high-elevation areas, wait until June or even early July.
Here is a region-by-region breakdown to help you nail the timing.
Coastal California
Coastal areas like San Francisco, Los Angeles, and San Diego have mild, frost-free winters. The main challenge here is cool, foggy summers.
- Direct sow: April through June. Wait until the fog burns off and soil warms.
- Transplants: Start seeds indoors in March, transplant in April or May.
- Fall planting: You can plant a second crop in July or August for a late harvest, but watch for early fall fog.
Inland Valleys
The Central Valley, Sacramento, and inland Southern California get hot summers. This is ideal for amaranth.
- Direct sow: Late April through June. Soil warms quickly.
- Transplants: Start indoors in March, transplant in April.
- Succession planting: Plant every 3-4 weeks until July for continuous harvest.
Desert Regions
Palm Springs, Death Valley, and the Mojave Desert have extreme heat. Amaranth loves it, but timing is critical to avoid the hottest months.
- Direct sow: March through April. Plant after the last frost, which is early.
- Summer break: Avoid planting in June and July when temps exceed 110°F. Plants may bolt or stop producing.
- Fall planting: August through September for a second crop.
Mountain And High Elevation
Lake Tahoe, Mammoth Lakes, and the Sierra Nevada foothills have short growing seasons and cold nights.
- Direct sow: June through early July. Wait until soil is warm and frost risk is gone.
- Transplants: Start indoors in May. This gives you a head start.
- Variety choice: Use fast-maturing varieties like ‘Red Garnet’ or ‘Golden Giant’ that mature in 60-70 days.
How To Determine Your Exact Planting Date
You don’t need a crystal ball. Use these steps to find your perfect window.
- Check your last frost date. Look up your area’s average last spring frost date. For most of California, this is between February and April.
- Wait two weeks after that date. This gives soil time to warm.
- Test soil temperature. Use a soil thermometer. Insert it 2 inches deep. If it reads 65°F or higher, you’re good.
- Watch the weather. Avoid planting before a cold snap or heavy rain.
If you don’t have a thermometer, a simple rule: when nighttime lows stay above 55°F for a week, it’s safe to plant.
Planting Methods: Direct Sow Vs. Transplants
You have two main options. Each has its own timing.
Direct Sowing
This is the easiest method. Amaranth seeds are tiny, so plant them shallow—about 1/4 inch deep. Space seeds 6-12 inches apart, depending on the variety.
- Timing: Sow after soil reaches 65°F.
- Germination: Takes 5-10 days in warm soil.
- Thinning: Thin seedlings to 12-18 inches apart once they have 4 leaves.
Starting Indoors
This gives you a head start, especially in cool coastal areas or mountains.
- Timing: Start seeds 4-6 weeks before your planned transplant date.
- Containers: Use small pots or seed trays with drainage.
- Transplanting: Harden off seedlings for a week. Transplant when they have 4-6 true leaves and soil is warm.
Soil Preparation And Site Selection
Amaranth is not picky, but it performs best in well-drained soil with full sun. It needs at least 6-8 hours of direct sunlight daily.
- Soil pH: Aim for 6.0-7.5. Test your soil if possible.
- Amendments: Add compost or aged manure a few weeks before planting. Avoid high-nitrogen fertilizers; they produce leafy growth but fewer seeds.
- Drainage: Amaranth hates wet feet. If your soil is clay, plant in raised beds or mounds.
Watering And Care After Planting
Once planted, amaranth needs consistent moisture until established. After that, it’s quite drought-tolerant.
- First 2 weeks: Water daily or every other day to keep soil moist.
- After establishment: Water deeply once a week. In hot weather, twice a week.
- Mulching: Apply a 2-inch layer of straw or wood chips to retain moisture and suppress weeds.
Weeds are the main competitor. Keep the area weed-free for the first month. After that, amaranth’s broad leaves shade out most weeds.
Common Mistakes With Timing
Even experienced gardeners slip up. Here are the most common timing errors.
- Planting too early: Seeds rot in cold, wet soil. Wait for warmth.
- Planting too late: In short-season areas, plants may not mature before frost.
- Ignoring microclimates: Your backyard might be warmer or cooler than the general forecast. Observe your own garden.
- Overwatering after planting: Soggy soil delays germination and invites disease.
Harvesting At The Right Time
When you harvest depends on your goal.
For Leaves
Harvest young leaves when plants are 6-12 inches tall. Pick the outer leaves first, leaving the center to grow. You can harvest leaves continuously until the plant flowers.
For Seeds
Seed heads form in late summer or early fall. Harvest when the seed heads are dry and seeds start to fall off. Cut the entire head and place it in a paper bag to finish drying.
In California, seed harvest typically happens from August to October, depending on your planting date.
Varieties That Work Best In California
Not all amaranth varieties are equal. Some mature faster, some handle heat better.
- ‘Red Garnet’: Fast-maturing (60 days). Great for leaves and seeds. Tolerates heat.
- ‘Golden Giant’: Tall, productive. Matures in 70-80 days. Good for inland valleys.
- ‘Hopi Red Dye’: Traditional variety. Excellent for seeds. Matures in 80-90 days.
- ‘Love Lies Bleeding’: Ornamental and edible. Matures in 90-100 days. Best for coastal areas.
Dealing With Pests And Problems
Amaranth is generally pest-resistant, but a few issues can pop up.
- Aphids: Spray with a strong stream of water or insecticidal soap.
- Leaf miners: Remove affected leaves. Use row covers early in the season.
- Powdery mildew: Common in foggy coastal areas. Space plants for airflow and avoid overhead watering.
- Birds: They love amaranth seeds. Cover seed heads with netting as they mature.
Succession Planting For Continuous Harvest
To extend your harvest, plant every 3-4 weeks. This works best in inland valleys and coastal areas with long growing seasons.
- Plant your first batch in late April.
- Plant a second batch in late May.
- Plant a third batch in late June.
This gives you fresh leaves all summer and staggered seed harvests in fall.
Fall Planting In Southern California
In warm coastal and desert areas, you can plant a fall crop. Aim for August or September. The key is to have plants mature before the first frost, which is usually December or later in these regions.
Fall-planted amaranth often produces better leaves because temperatures are cooler. Seed production may be lower due to shorter days.
Frequently Asked Questions
Can I plant amaranth in winter in California?
Only in frost-free areas like coastal Southern California. Even then, growth is slow. It’s better to wait for spring.
What is the latest I can plant amaranth in California?
For most areas, early July is the latest for a reliable seed harvest. For leaves only, you can plant until August in warm regions.
Do I need to soak amaranth seeds before planting?
No. Amaranth seeds are tiny and germinate quickly without soaking. Soaking can cause them to rot.
How deep should I plant amaranth seeds?
Plant them 1/4 inch deep. They need light to germinate, so don’t bury them too deep.
Can amaranth grow in partial shade?
It will grow, but it will be leggy and produce fewer seeds. Full sun is best for strong plants.
Final Tips For Success
Planting amaranth in California is rewarding if you get the timing right. Start with a soil temperature check, match your planting date to your region, and don’t rush the season.
Keep an eye on your local weather. A late spring cold snap can ruin an early planting. If in doubt, wait an extra week. Amaranth grows fast, so you won’t lose much time.
Remember, the best time to plant amaranth in california is when the soil is warm, the nights are mild, and the sun is strong. Follow these guidelines, and you’ll have a bumper crop of leaves and seeds.
Happy growing, and enjoy your amaranth harvest from your California garden.