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Intermediate Guide
Season Extension
Extend your growing season with cold frames, row covers, and other techniques. Harvest earlier in spring and later into fall—or even through winter.
16 min read
Cold climate essential
Why Extend Your Season?
Most gardeners only use their garden space for 4-5 months of the year. With simple protection techniques, you can easily double your productive season—and in many climates, grow food year-round.
Earlier Harvests
Start warm-season crops weeks before last frost
Later Harvests
Keep harvesting tomatoes into fall
Overwinter Crops
Grow spinach, kale, and more through winter
Better Planning
Extend your productive season by months
How Cold Protection Works
Heat Sources:
- • Solar radiation - Trapped by covers
- • Soil heat - Released at night
- • Plant respiration - Generates warmth
- • Thermal mass - Water jugs store heat
Protection Factors:
- • Wind block - Prevents heat loss
- • Dead air space - Insulates
- • Multiple layers - Double protection
- • Ground contact - Access to soil warmth
Protection Methods Compared
Spring Extension Timeline
6-8 weeks before last frost
- Start warm-season seeds indoors under lights
- Prepare cold frames and check for damage
- Direct sow cold-hardy crops under row cover
4-6 weeks before last frost
- Set up low tunnels for transplants
- Begin hardening off earliest seedlings
- Plant potatoes under heavy mulch
2-4 weeks before last frost
- Transplant tomatoes under wall-o-waters or cloches
- Set out peppers with hot caps ready
- Direct sow beans under row cover
At last frost date
- Remove protection on warm days
- Keep covers handy for surprise cold snaps
- Monitor weather forecasts closely
Fall Extension Timeline
8-10 weeks before first frost
- Plant fall brassicas, lettuce, spinach
- Succession plant quick crops for harvest before frost
- Order row cover and repair supplies
4-6 weeks before first frost
- Set up low tunnels over tender crops
- Mulch heavily around root vegetables
- Harvest and store winter squash
2-4 weeks before first frost
- Cover all tender crops nightly
- Harvest green tomatoes before hard frost
- Protect peppers and basil completely
After first frost
- Continue harvesting cold-hardy crops
- Add extra covers as temps drop
- Transition to winter growing mode
Crops for Winter Growing
These crops can survive and even thrive through winter with appropriate protection. They won't grow much in the shortest days, but will resume growth in late winter for early spring harvests.
| Crop | Min. Temp | Notes |
|---|---|---|
| Spinach | 15°F with protection | Stops growing but survives, sweetens with cold |
| Kale | 10°F with protection | Flavor improves after frost, very hardy |
| Mache (Corn Salad) | 5°F with protection | Extremely cold hardy, mild flavor |
| Carrots | 20°F in ground | Mulch heavily, dig as needed all winter |
| Leeks | 10°F | Very cold hardy, hill with soil or mulch |
| Parsley | 10°F with protection | Biennial, survives winter to flower in spring |
| Claytonia | 0°F with protection | Also called miner's lettuce, extremely hardy |
| Arugula | 20°F with protection | Will regrow after freezing, strong flavor |