When to put transplants or seed in the ground in covered areas of California, worked out from the average last spring and first fall frost for each USDA zone in the state, and what to line up before you commit ground. This page covers only the listed Zone 6–9 areas, not the whole state. Elevation changes frost dates fast here, so check your own last-frost date against the zone average. Written for farms that sell what they grow.
Your zone in California: frost dates
Zones 7b–9b run through California. Frost dates are long-term averages for planning, not a forecast for your field.
Zone 7b
The Sierra foothills
Last frost
~April 8
First frost
~October 22
Frost-free days
197
Winter low
5°F to 10°F
Zone 8b
Redding and the northern Sacramento Valley
Last frost
~March 15
First frost
~November 15
Frost-free days
245
Winter low
15°F to 20°F
Zone 9a
Sacramento, Fresno and the Central Valley
Last frost
~February 25
First frost
~December 1
Frost-free days
279
Winter low
20°F to 25°F
Zone 9b
The Salinas Valley and inland coast
Last frost
~February 5
First frost
~December 15
Frost-free days
313
Winter low
25°F to 30°F
What it costs to grow an acre in California
Every number below is transcribed from a published land-grant enterprise budget for California. Operating cost is what it takes to grow and harvest the crop; ownership cost is machinery, land and overhead. Multiply by your acres to size the cash you need before the first sale.
No published California budget is transcribed here yet, so this page shows planting dates only — we do not publish cost figures we cannot source. Neighboring state budgets from NC State, UGA and UF/IFAS are on the crop profitability page.
Every figure is transcribed from a published land-grant enterprise budget for that state. These are planning budgets built from grower panels and dealer quotes, not surveys of what farms actually spent — your invoices override them everywhere they exist.
When to plant California's main crops
Calculated for Zone 9a (Sacramento, Fresno and the Central Valley). Pick your own zone on the crop page.
If your farm sits in a zone that is not listed here, start from the calendar index and pick the closest match, then confirm with your county extension office.
Before you commit ground
A planting date tells you when a crop can grow — not whether it pays. Work out your breakeven price, then line up who is buying before you plant.
What USDA planting zone is Grass Valley, California?
The calendar carries Grass Valley in Zone 7b. Average last spring frost is around April 8 and average first fall frost around October 22, which is about 197 frost-free days.
What USDA planting zone is Redding, California?
The calendar carries Redding in Zone 8b. Average last spring frost is around March 15 and average first fall frost around November 15, which is about 245 frost-free days.
When should I plant tomatoes in California?
In Zone 9a (Sacramento, Fresno and the Central Valley), March 4 – March 25 may 25 – june 22
Dates are calculated from average first and last frost dates for each zone. Your microclimate, elevation and soil temperature can shift any window by a week or more — treat these as starting points and keep your own records.