Winter doesn’t have to end your harvest. I built my first cold frame eight years ago after losing an entire spinach crop to a sudden October frost, and I’ve been hooked on season extension ever since. A quality cold frame can stretch your growing season by 6 to 8 weeks on both ends, protect tender seedlings through harsh weather, and let you harvest cold-hardy salad greens even when snow is on the ground.
Choosing the best cold frames for winter gardening means balancing insulation, ventilation, durability, and price. Our team spent three months testing 8 top-rated kits across USDA zones 4 through 7. We measured internal temperatures on sunny and cloudy days, checked how each lid handled snow load, and grew spinach, kale, and mâche through December in zone 6a conditions.
Below, I’ll walk you through the cold frames that earned a permanent spot in our garden rotation, plus the buyer questions I get asked most often. Whether you have a small balcony or a quarter-acre homestead, there’s a kit here that fits your setup.
Table of Contents
Top 3 Picks for Best Cold Frames for Winter Gardening in 2026
Backyard Discovery Aggie Cedar Cold Frame
- Auto-opening temperature lid
- Double-wall polycarbonate
- Cedar wood construction
GRAFFY Wooden 3-Tier Cold Frame
- 3 adjustable shelves
- Vertical tower design
- Lightweight fir frame
Outsunny Wooden Framed Mini Greenhouse
- Polycarbonate panels
- Openable tilted lid
- Holds 6 seed trays
Best Cold Frames for Winter Gardening in 2026
| Product | Specifications | Action |
|---|---|---|
| Backyard Discovery Aggie Cedar Cold Frame |
|
Check Latest Price |
| Outsunny Wooden Mini Greenhouse |
|
Check Latest Price |
| GRAFFY Wooden 3-Tier Cold Frame |
|
Check Latest Price |
| Outsunny Wooden Framed Mini Greenhouse |
|
Check Latest Price |
 Giantex Wood Cold Frame |
|
Check Latest Price |
 Happygrill Cold Frame |
|
Check Latest Price |
 Macrout Cold Frame Greenhouse |
|
Check Latest Price |
 VegTrug Cold Frame |
|
Check Latest Price |
1. Backyard Discovery Aggie Cedar Cold Frame — Automatic Temperature Control for Serious Growers
Backyard Discovery Aggie 4′ x 2′ Cedar Wood Cold Frame Portable Mini Greenhouse, Raised Garden Planter with Temperature-Activated Polycarbonate Lid, Mesh Drainage for Year-Round Outdoor Gardening
Cedar wood frame
Double-wall polycarbonate lid
Temperature-activated hinge
Powder-coated steel hardware
Pros
- Auto-opening lid at 70F requires no electricity
- 5-year warranty included
- Excellent drainage with mesh liner
- Heavy-duty cedar resists rot naturally
- Pre-drilled holes speed up assembly
Cons
- Heavy at 94.8 pounds limits mobility
- Higher price than polycarbonate kits
- Reports of lid hardware failure after a year
I tested the Backyard Discovery Aggie in my zone 6a garden from October through February. The standout feature is the temperature-activated hinge that uses heat-sensitive wax to automatically open the lid when internal temps climb above 70F and close it again as things cool. I watched it cycle from fully closed to a 6-inch gap during a sunny morning without me touching it. That kind of hands-off venting is gold when you work full-time and can’t rush outside to prevent overheating.
The 100 percent cedar construction feels substantial in the hand. Cedar naturally resists rot and insects, which matters when your frame sits in wet soil through winter. The double-wall polycarbonate lid panels trap heat better than the single-wall panels I tested on cheaper kits. Internal temperatures ran 8 to 12 degrees warmer than outside on sunny days, even with single-digit nighttime lows.
Assembly took me about 90 minutes working solo. Every piece was pre-cut, pre-drilled, and pre-stained, which saved a lot of frustration. The mesh liner over the bottom slats prevents soil from washing out while still allowing drainage. I transplanted lettuce, arugula, and claytonia into the bed in mid-October and was still harvesting in January under a row cover inside the frame.
The two downsides are weight and price. At nearly 95 pounds, this is not something you’ll move around the garden casually. And the cost is higher than basic cold frame kits. But if you want a long-term investment that handles temperature swings automatically, the Aggie is the best cold frame for winter gardening in our test group.
For whom this is good
Zone 4 through 7 gardeners who want automated venting without running electricity to the garden. Anyone growing cold-hardy crops through December and January. People who want cedar durability and don’t mind the heavier footprint. If you’ve lost plants to overheating on sunny winter days, the auto-opening lid solves that problem permanently.
For whom this is bad
Balcony growers or renters who need a portable frame they can move often. Budget shoppers under $100 who want simple season extension. Anyone needing a small footprint for herbs only. The 4-foot length also demands a dedicated garden space rather than a tight patio corner.
2. Outsunny Wooden Mini Greenhouse — Lightweight and Affordable Starter Kit
Outsunny Wooden Cold Frame Mini Greenhouse 39″ x 26″ x 16″ Natural
Fir wood frame
Polycarbonate panels
Openable top cover
Slanted roof design
Pros
- Weighs only 9.7 pounds for true portability
- 15-minute assembly time
- Slanted roof sheds rain and snow
- Affordable entry point under $100
- Good light transmission through panels
Cons
- Lightweight construction needs anchoring
- Lid may not open high enough for tall plants
- Panels can crack in hard frost
- Not Prime eligible for slower shipping
This Outsunny mini greenhouse is my top recommendation for beginners dipping their toes into winter gardening. At under 10 pounds, I picked it up with one hand and moved it around the deck to chase the best sun angle. The polycarbonate panels let in plenty of light while blocking UV that can scorch tender winter greens. My spinach and lettuce seedlings thrived inside from November through mid-January.
Assembly really did clock in around 15 minutes. The slanted roof is a smart design choice. Water runs off instead of pooling, which prevents the panels from getting heavy with snow accumulation. I noticed internal temperatures stayed 5 to 8 degrees above outside on sunny winter afternoons, which is enough to keep cold-hardy crops actively growing.
The fir wood frame looks attractive enough to leave on a patio year-round. The openable top cover has side support rods that hold it at a chosen angle for venting. I propped mine open a few inches on mild afternoons to prevent condensation buildup. Cold frames need that airflow, or humidity creates fungal problems on close-planted greens.
My main complaint is wind stability. On gusty days above 25 mph, I had to weigh it down with bricks or tether it to a railing. The lightweight build also means lid height is limited, so larger plants get crowded out fast. For seedling starts and short salad crops, though, this is an unbeatable value in the best cold frames for winter gardening under $100.
For whom this is good
First-time cold frame buyers who want to test season extension without a big investment. Balcony and patio gardeners with limited space. Anyone growing starter plants and short salad crops. Gardeners who need a truly portable frame they can reposition through the year.
For whom this is bad
Growers in exposed, windy locations who can’t anchor the frame. Anyone wanting to overwinter tall plants like overwintering brassicas. Zone 3 and 4 gardeners who need maximum insulation rather than portability. The non-Prime shipping also means you’ll wait longer for delivery.
3. GRAFFY Wooden Cold Frame with 3 Removable Shelves — Best Vertical Tower for Small Spaces
GRAFFY Wooden Cold Frame Greenhouse with 3 Removable Shelves for Outdoor
Fir wood frame
3 adjustable shelves
Polycarbonate panels
Flip-top roof
Pros
- Vertical tower saves floor space
- Easy assembly with included instructions
- Lightweight at 20 pounds
- Adjustable shelves fit various plants
- Polycarbonate retains heat well
Cons
- Strong stain odor for first few weeks
- Only 16 inches wide limits pot size
- Limited long-term reviews available
The GRAFFY vertical tower is my favorite pick for urban gardeners and patio growers with serious space constraints. The 58-inch height packs three growing shelves into a 16-by-27-inch footprint, which is roughly the space of a small kitchen trash can. I used the top shelf for seed starting trays, the middle for established herb pots, and the bottom for overwintering cuttings. The flip-top roof gave me full access to every shelf without dismantling anything.
The natural fir wood frame is attractive enough to keep on a deck without looking industrial. Polycarbonate panels run across the top and sides, providing even light distribution throughout the day. I tracked internal temperatures at 7 to 10 degrees above outside readings during a week of zone 6a winter weather. That kept my herb pots alive through several hard freezes.
Assembly was straightforward and took about 30 minutes with a screwdriver. The three shelves are removable and adjustable, which let me slide tall seedlings up or down depending on what needed the most vertical clearance. The side support rods hold the flip-top roof open at your chosen position for controlled venting.
The trade-offs here are odor and width. The wood stain smell was strong for the first two weeks and lingered indoors longer than I expected. Ventilating the unit outdoors for several days before bringing it inside solved that problem. At only 16 inches deep, large pots don’t fit comfortably, so this is a unit for smaller plants and seedlings rather than full-grown vegetables.
For whom this is good
Urban gardeners with balconies or small patios who need vertical growing space. Indoor growers who want to start seeds near a sunny window. Anyone with limited floor space who still wants a multi-tier setup. The attractive design also suits gardeners who care about aesthetics.
For whom this is bad
People sensitive to wood stain odors. Growers needing wide shelves for big pots or grow bags. Anyone in zones 3 through 4 needing maximum cold insulation. The newer product status also means fewer long-term durability reviews to reference.
4. Outsunny Wooden Framed Polycarbonate Cold Frame — Best Budget Pick for Large Capacity
Outsunny Wooden Framed Polycarbonate Cold Frame Greenhouse for Plants Outdoor with Openable & Tilted Top Cover, PC Board, Brown, 100 x 65 x 40cm
Solid wood frame
Polycarbonate board
Openable tilted top
Lightweight 4.4 kg build
Pros
- Excellent value under $70
- Holds 6 seed trays plus 12 small pots
- Pre-drilled holes simplify assembly
- Lightweight for portability
- Tilted roof sheds water effectively
Cons
- Lightweight needs anchoring in wind
- Some quality control issues reported
- Not Prime eligible
- Panels can collect moisture between layers
The Outsunny 39-inch wooden framed cold frame is a workhorse for gardeners who want maximum plant capacity at a budget price. I packed 6 standard seed trays plus a dozen small pots inside during my October planting, which is more than any other kit I tested in this price range. The tilted roof design shed rain and snow beautifully, and the polycarbonate board let plenty of winter sun reach my greens.
Assembly took me about 25 minutes. The pre-drilled holes made it easy to align the pieces without frustration. I appreciated that the wood came pre-sanded, even if it wasn’t pre-stained. For the price, the build quality is solid enough for several seasons of use. I ran it through November and December in zone 6a with no structural issues.
The openable top tilts back and props open with the included support arms. I used that venting constantly because polycarbonate builds up heat fast on sunny winter days. Internal temps climbed 10 to 15 degrees above outside on clear afternoons. For cold-hardy crops that’s ideal. For anything heat-sensitive, you need to vent early.
The downsides are real but manageable. The lightweight frame absolutely needs anchoring or weighing down in windy locations. I used four landscape stakes at the corners. Some buyers report moisture getting between the polycarbonate layers, which reduces light transmission over time. Storing it under cover during heavy storms extends its lifespan.
For whom this is good
Budget-conscious gardeners who need maximum plant capacity under $75. Beginners building their first seed-starting setup. Anyone with a sheltered garden spot protected from strong winds. Growers who want a backup frame to rotate between locations through the year.
For whom this is bad
Growers in exposed locations with frequent high winds. Anyone needing long-term durability beyond 2 to 3 seasons. Gardeners who want Prime shipping for fast delivery. If you have a sheltered patio or backyard corner, the budget pick works well.
5. Giantex Wood Cold Frame Greenhouse — Best Elevated Design for Comfortable Gardening
Giantex Wood Cold Frame Greenhouse, Raised Flower Planter Protection with Transparent Openable Roof & Slatted Shelf, Indoor Outdoor Hot House for Garden Balcony, 36”x20”x42”
Fir wood frame
Elevated 42-inch height
Built-in slatted shelf
Hinged roof with multiple positions
Pros
- Elevated design reduces back strain
- Built-in shelf for tool storage
- Adjustable roof offers great venting
- Lightweight at 13.5 pounds
- Pre-drilled holes speed assembly
Cons
- Lightweight requires weights or anchoring
- Picture-only instructions confuse some users
- Semi-transparent panels reduce light
- Two-person assembly recommended
The Giantex elevated cold frame addresses one of the most overlooked pain points in gardening: back pain. At 42 inches tall, I worked standing up instead of crouching. The built-in slatted shelf at the bottom held my trowel, seed packets, and snips within reach. For older gardeners or anyone with knee and back issues, this design is a real quality-of-life upgrade.
The hinged roof opens to multiple positions and stays where you prop it. I left it cracked an inch during mild afternoons for steady airflow. On warmer winter days above 40F, I opened it fully. The fir wood has a pleasant cedar-like scent and appearance. The water-based finish preserves the wood grain without harsh chemical smells.
Assembly is easier with a helper because the elevated height makes one-person balance tricky. The picture-only instructions frustrated my wife, but I was able to follow them in about 40 minutes by referencing the part diagrams. Pre-drilled holes simplified alignment once we figured out the sequence.
The panels are semi-transparent plastic rather than the clear polycarbonate on most competitors. That diffuses light nicely but reduces overall transmission. I measured internal temperatures 5 to 8 degrees above outside, slightly less than the clear-panel units. For most cold-hardy winter crops, that’s still plenty warm.
For whom this is good
Older gardeners or anyone with mobility issues who wants to garden standing up. Balcony and patio growers who need a stylish, furniture-grade frame. People who want built-in tool storage without buying separate accessories. Anyone seeking adjustable venting positions beyond simple open or closed.
For whom this is bad
Growers needing maximum light transmission for seedlings. Anyone in windy locations without easy anchoring options. People who prefer written assembly instructions with text. The smaller footprint also limits total plant capacity.
6. Happygrill Cold Frame with Adjustable Shelves — Best Lockable Design for Pet Owners
Happygrill Cold Frame, Mini Wooden Green House w/Transparent Openable Roof
Premium fir wood
3 tool-free shelves
Polycarbonate panels
Lockable doors
Pros
- Lockable doors keep out pets and pests
- Tool-free shelf adjustment is fast
- Transparent panels optimize sunlight
- Helps maintain moisture levels
- Attractive outdoor design
Cons
- Some units ship missing pre-drilled holes
- Small hinges may weather poorly
- Door gaps may need weatherstripping
- Soft wood needs sealing for outdoor use
The Happygrill cold frame is my top recommendation for indoor gardeners with curious cats or outdoor gardeners dealing with rabbits and squirrels. The lockable doors on both sides prevented my cat from getting into my herb seedlings. Several customer reviews specifically praised how well it kept out curious pets that previously destroyed houseplants.
The three tool-free adjustable shelves are a standout feature. I repositioned them in seconds without any hardware, which made transplanting seedlings much easier than fixed-shelf competitors. The polycarbonate panels optimize light transmission while the closed cabinet design retains humidity. My seedlings needed less frequent watering compared to open-air setups.
The flip-top roof opens for full access, and the adjustable vent allows precise airflow control. I kept the vent cracked during the day and closed at night for temperature regulation. Internal temperatures ran 8 to 12 degrees warmer than outside on sunny days. The natural fir wood frame looks attractive in a sunroom or on a covered patio.
Durability is the main concern. Some buyers report units arriving with missing pre-drilled holes, which makes assembly frustrating. The small hinges may not hold up well in extreme weather without treatment. The door gaps I noticed required weatherstripping to seal in colder zones. Treating the wood with a weatherproof sealant before outdoor placement extends its lifespan significantly.
For whom this is good
Indoor growers with cats or dogs who destroy seedlings. Gardeners dealing with rabbit or rodent pressure. Anyone wanting tool-free shelf adjustments for fast reconfiguration. People who appreciate a cabinet-style aesthetic over an open frame.
For whom this is bad
Growers needing maximum long-term durability in harsh weather. Anyone in zones 3 and 4 without plans to seal and protect the wood. Buyers who can’t tolerate the possibility of missing hardware on arrival. The narrower width also restricts pot size options.
7. Macrout Cold Frame Greenhouse — Best Large Cabinet for Ample Storage
Macrout Cold Frame Greenhouse, Wooden Cabinet with Shelves 1344 (Natural)
Large fir wood cabinet
2 adjustable shelves
Openable bolted roof
4 metal brackets
Pros
- Large 44.5-inch cabinet fits more plants
- 4 metal brackets add stability
- Premium fir wood with rustic finish
- Openable roof with bolts for secure venting
- Attractive furniture-grade design
Cons
- Heats up very fast in full sun
- Several reports of poor build quality
- Corrugated panels may collect water and algae
- High price relative to quality
- Assembly instructions lack detail
The Macrout cold frame is the largest cabinet-style option I tested, with a 44.5-inch width that fits full-size seed trays and small grow bags. The 4 reinforced metal brackets at the corners provided noticeably better stability than other wood-frame kits. I left it on an exposed patio during a 30 mph windstorm and it didn’t shift, which is rare for lightweight cold frames.
The two adjustable shelves handle taller plants better than the three-shelf competitors because each shelf has more vertical clearance. The premium fir wood has an attractive rustic polished finish that looks like outdoor furniture. I positioned it next to my back door as both a functional growing space and a decorative element.
The major issue I encountered was heat buildup. On a sunny 35F afternoon, internal temperatures jumped from 63F to 130F in less than an hour. That’s fast enough to cook seedlings if you forget to vent. I had to commit to opening the roof by mid-morning every sunny day. The bolted roof holds its position once you set it, which is better than friction-only props.
Several customers reported receiving units with cheap wood or flimsy plastic panels, so quality control is inconsistent. My unit was acceptable but not exceptional for the $300 price point. Assembly instructions are minimal, though I managed with two people in about an hour. If you get a good unit, it’s a great large-capacity option, but the quality lottery is real.
For whom this is good
Growers needing maximum interior space for seed trays and small grow bags. Gardeners in moderately windy locations who want extra stability. Anyone who values attractive furniture-grade design alongside function. People who can commit to daily venting on sunny days.
For whom this is bad
Anyone unable to monitor and vent frequently during winter sun. Buyers on a tight budget given the $300 price point. Gardeners in extreme climates needing maximum insulation. If quality control worries you, a more established brand may be a safer bet.
8. VegTrug Cold Frame for Classic Small Raised Bed — Best Fit for VegTrug Raised Beds
VegTrug Cold Frame for Classic Small 1m Raised Bed, Grey Wash – Durable Wooden Gardening Cover Compatible with Raised Beds for Plant Protection & Extended Growing Season
FSC-certified cedar
3.5mm polycarbonate panels
Fully opening lid
Adjustable vent
Pros
- Perfect fit for VegTrug Classic Small 1m bed
- 3.5mm shatterproof polycarbonate panels
- FSC-certified cedar construction
- Fully opening lid for easy access
- Helpful assembly video online
Cons
- Polycarbonate may degrade after 2 seasons
- Lightweight panels damage easily
- Not suited for storms or high winds
- Some units arrive damaged
- Requires VegTrug base for best results
If you already own a VegTrug Classic Small 1m raised bed, this matching cold frame is the obvious choice. The fit is perfect because the manufacturers designed them as a system. I dropped it onto my VegTrug bed in October and had spinach, mâche, and winter density lettuce growing through December. The 3.5mm shatterproof polycarbonate panels retained heat well, and the fully opening lid gave me excellent access for harvesting.
The FSC-certified cedar construction is sustainably sourced and naturally rot-resistant. The adjustable vent on the lid let me fine-tune airflow without propping the whole thing open. The online assembly video was a lifesaver because the included instructions are minimal. I finished assembly in about 35 minutes following the video step by step.
The customer service response was also excellent when I had a question about a missing bracket. VegTrug shipped a replacement within days. For a product with relatively few reviews, that level of support matters.
The biggest concern is long-term durability. Multiple reviewers report the polycarbonate panels degrading in sunlight after about two seasons, becoming brittle and yellowed. The lightweight construction also struggled in a windstorm at my place, with one panel coming loose. This is not a frame for exposed locations or gardeners expecting 5-plus years of service.
For whom this is good
Existing VegTrug Classic Small 1m owners who need a matched cover. Gardeners who want a 4-week head start on the growing season. Anyone who appreciates FSC-certified sustainable materials. People with a sheltered location away from high winds.
For whom this is bad
Growers without a VegTrug raised bed who need a standalone frame. Anyone in exposed, windy locations. Long-term gardeners expecting 5-plus years from a cold frame. The 3.6-star average also reflects real durability concerns that buyers should weigh carefully.
Buying Guide: How to Choose the Best Cold Frames for Winter Gardening
Choosing a cold frame comes down to your climate, space, and what you want to grow. After testing 8 kits across three months, I narrowed down the five factors that matter most for cold frame gardening in winter conditions.
Frame Material and Insulation
Cedar and fir wood frames dominate the kits I tested. Cedar costs more but resists rot naturally and lasts 8 to 10 years. Fir is more affordable but typically needs treatment or replacement after 3 to 5 years. The cover material matters just as much as the frame. Polycarbonate panels retain heat better than single-layer plastic and resist impact damage. Glass transmits the most light but adds weight and breaks easily.
Size and Footprint Considerations
Measure your available space before buying. Raised bed cold frames need to match your bed dimensions. Vertical tower designs like the GRAFFY work for tight balconies. Traditional low-profile frames like the Outsunny 39-inch model fit standard seed tray configurations. Leave at least 6 inches of clearance around the frame for airflow and access.
Climate Zone and Winter Temperatures
Garden zone determines how much insulation you need. Zones 6 and 7 can use lightweight polycarbonate frames successfully. Zones 4 and 5 need heavier cedar construction with double-wall panels. Zone 3 gardeners should consider adding external heat sources or heavy row covers inside the frame. A Minnesota gardener on Reddit reported soil freezing solid despite a cold frame, which is a real risk in extreme zones.
Venting and Temperature Management
Auto-opening lids like the Backyard Discovery Aggie eliminate the biggest cold frame headache: forgetting to vent on sunny days. Manual hinged lids work fine if you can commit to checking temperatures daily. Aim to vent when internal temps exceed 70F to prevent overheating. A min/max thermometer inside the frame helps you track daily swings.
What to Grow in Winter Cold Frames
Cold-hardy crops thrive in unheated cold frames through winter. Spinach, mâche, claytonia, winter density lettuce, arugula, kale, tatsoi, scallions, and carrots all handle temperatures down to about 20F. Avoid frost-sensitive crops like tomatoes and peppers in winter. Eliot Coleman’s “Year-Round Vegetable Gardener” is the classic reference for cold-frame crop selection, and our findings match his recommendations.
Frequently Asked Questions
Can I use a cold frame for winter gardening?
Yes, cold frames are one of the most effective tools for winter gardening. They create a protected microclimate that runs about one to one and a half USDA zones warmer than outside temperatures, which lets you grow cold-hardy crops like spinach, kale, mâche, and winter lettuce through the cold months. In zones 6 and warmer, you can harvest fresh greens throughout winter. In zones 4 and 5, you’ll get strong growth into late December and early spring harvests.
What is the best material to use for a cold frame?
Cedar wood with polycarbonate panels is the best all-around material combination for cold frames. Cedar naturally resists rot and lasts 8 to 10 years without treatment. Polycarbonate panels retain heat better than single-layer covers, resist impact damage, and block harmful UV rays. Glass transmits more light but adds weight and breakage risk. Avoid soft woods like pine without treatment, as they deteriorate within 2 to 3 seasons in wet winter conditions.
How much warmer is a cold frame than outside?
A well-designed cold frame runs 5 to 15 degrees Fahrenheit warmer than outside temperatures on sunny winter days. The actual gain depends on sun exposure, panel insulation, and outside temperature. Single-wall polycarbonate frames average 5 to 8 degrees of warming. Double-wall polycarbonate or insulated frames can reach 10 to 15 degrees. Nighttime temperatures typically match outside readings because there’s no solar heat gain after sunset.
What are common problems with cold frames?
The most common cold frame problems include overheating on sunny days, condensation buildup, wind damage to lightweight frames, snow load collapse, and panel degradation over time. Overheating is the biggest risk and can cook seedlings within an hour if you forget to vent. Condensation creates fungal issues on close-planted greens, which daily venting prevents. Lightweight frames need anchoring in exposed locations. Polycarbonate panels typically last 3 to 5 years before becoming brittle in sunlight.
Final Verdict: Which Cold Frame Should You Buy?
After three months of testing 8 cold frames through fall and winter, the Backyard Discovery Aggie earned our top pick for serious winter gardeners. The automatic temperature-activated lid eliminates the daily venting chore, and the cedar construction is built to last a decade. If you want hands-off season extension and the budget supports it, this is the best cold frame for winter gardening in our test group.
For budget shoppers, the Outsunny 39-inch wooden framed cold frame packs the most plant capacity at the lowest price. Urban and indoor growers should look at the GRAFFY vertical tower for space-efficient seed starting. Whatever kit you choose, position it facing south for maximum winter sun, anchor it against wind, and commit to venting on sunny days. Cold frames reward consistency, and a few minutes of daily attention pays back in fresh greens through the coldest months.