Companion Planting by Season: Spring, Summer, Fall Combos

The companion planting pairings that work for tomatoes in July do not work for cabbage in April. The soil is colder, the pests are different, and half your summer favourites cannot germinate yet. This is why most generic companion planting charts confuse new gardeners: they list everything in one big block without telling you what season it actually applies to.

This guide gives you the working pairings for spring, summer, and fall, with the soil temperature thresholds, the pest pressure each season actually faces, and the rotation pattern that connects one season to the next in the same bed. If you have come from our companion planting chart, this is the seasonal layer on top of it.

The Quick Map of the Three Seasons

Penn State Extension draws the basic line: cool-season crops germinate at soil temperatures of 40 to 50 F and grow best between 50 and 70 F. Warm-season crops want 65 F+ soil and stall below 60 F. The Weekend Gardener's calendar runs three working windows:

Sources: Penn State Extension, Cool-season vs Warm-season Vegetables, Iowa State Extension, Soil Temperature and Planting Conditions for Spring, UMD Extension, Vegetable Planting Calendar.

Spring Companions: Cool Soil, Fast Crops

Spring is the easiest season for new companion planters because the crops grow fast, mature on overlapping schedules, and clear the bed before summer crops need the space. The catch is timing: match the pairing to the actual soil temperature, not to the calendar date. Buy a soil thermometer and check the top 4 inches at 9 am.

Sources: Cornell Cooperative Extension, Cool Season Vegetables (PDF), UMN Extension Companion Planting, University of Delaware Extension, The New Companion Planting.

The spring rule of thumb: every bed should pair one fast crop (radish, lettuce, spinach) with one slow crop (broccoli, cabbage, kale, carrot, beet). The fast crop is out before the slow crop reaches full size, doubling the bed's effective yield in the same season. For a fuller spring walk-through, see our existing spring companion planting guide.

Summer Companions: Warm Soil, Heavy Yields

Summer is the high-yield season but also the high-pest-pressure season. Aphids, cabbage worms, squash bugs, hornworms, flea beetles, and Japanese beetles all hit at once. The aromatic herb companions and trap-crop flowers earn their place here.

Sources: People and Nature, Three Sisters yield study (peer-reviewed, 2024), PMC5746795, Companion Plants for Aphid Pest Management, PubMed 27860184, Calendula as a floral resource.

Pairings to Avoid in Summer

Sources: Gardenia, Do NOT Grow These Plants Together, Penn State Extension, Plant Rotation by Plant Families.

Fall Companions: Cool Soil Returning, Overwintering Starts

Fall is the season most gardeners give up too early on. Penn State Extension's season extenders guide documents that frost-tolerant brassicas (cabbage, kale, Brussels sprouts), root crops (carrot, beet, parsnip), and overwintering alliums (garlic, shallot) can produce well into November and December in much of the US, especially with a row cover.

Sources: Penn State Extension, Season Extenders, UMN Extension, Tips for Garlic Planting Season, UMD Extension, Growing Garlic in a Home Garden.

For the full fall planting playbook see our fall companion planting guide.

Cover Crops as Fall and Winter Companions

Cover crops are the often-skipped fourth companion of the fall garden. They sit in the empty space between your last fall vegetable and next spring's planting, fixing nitrogen, building organic matter, suppressing winter weeds, and protecting soil from rain compaction. The three workhorses for home gardens:

For the full menu and selection logic see USDA SARE's Managing Cover Crops Profitably and UMN Extension's cover crop selection guide for vegetable growers.

The 3-Year Rotation Across All Three Seasons

Seasonal pairing is only half of the planning job. The other half is rotating plant families between years so soil diseases do not build up in the same bed. Penn State Extension recommends a 3-year minimum rotation. Combined with seasonal pairing, a 3-bed home garden produces around 9 distinct crops per year while never replanting the same family in the same spot for at least 3 years.

A working example over 3 years in the same 4 by 8 ft bed:

Year 1: Spring peas (Fabaceae) → summer tomato + basil (Solanaceae + Lamiaceae) → fall cover crop (winter rye + crimson clover).

Year 2: Spring lettuce + carrot (Asteraceae + Apiaceae) → summer pepper + eggplant (Solanaceae) → fall garlic (Alliaceae) overwintering.

Year 3: Spring broccoli + onion (Brassicaceae + Alliaceae) → summer cucumber + squash + nasturtium (Cucurbitaceae) → fall kale + scallion (Brassicaceae + Alliaceae).

By year 4 you cycle back to year 1, the soil never sees the same disease pulse twice in a row, and the bed produces continuously. Peer-reviewed work on legume rotation in PMC10245104 documents the nitrogen-cycling benefit: a pea or bean year leaves 40 to 60 lb N per acre behind for the next year's heavy feeder. Plan the rotation around that gift.

Frequently Asked Questions

What can you plant together in spring?

Peas with carrots, peas with spinach, lettuce with radish, broccoli with onions, cabbage with dill or chamomile, beets with bush beans, and spinach near strawberry. Spring pairings work in cool soil (40 to 60 F) and mature on overlapping 8 to 12 week schedules so the fast crops clear the bed before warm-season crops arrive. Use a soil thermometer to confirm 40 to 50 F at 4 inch depth before sowing.

What can you plant together in summer?

Tomato with basil and marigold, pepper with basil and parsley, Three Sisters (corn with pole beans and winter squash), cucumber with dill and nasturtium, squash with nasturtium and radish, eggplant with basil and thyme. All of these pairings rely on aromatic herbs masking the crop's volatile signature plus trap-crop flowers drawing pests to the perimeter.

What can you plant together in fall?

Cabbage with dill and chamomile, kale with scallion and leek, lettuce with radish, garlic with a winter cover crop, carrot with onion. Fall pairings are essentially spring pairings repeated in cooling soil rather than warming soil, plus overwintering alliums (garlic, shallot, leek) planted in October for next summer's harvest.

What is the difference between cool-season and warm-season companion planting?

Cool-season pairings (spring and fall) work in soil between 40 and 65 F and feature peas, lettuce, spinach, brassicas, beets, carrots, and radish. Warm-season pairings (summer) work in soil 65 F+ and feature tomato, pepper, eggplant, corn, beans, squash, and cucumber. Mixing the two seasons (planting tomatoes in 50 F soil or lettuce in 80 F soil) fails regardless of how good the companion pairing is on paper.

How do you rotate crops between seasons?

Rotate by plant family on a 3-year cycle. A working pattern: year 1 legume in spring then nightshade in summer then cover crop in fall; year 2 lettuce or carrot in spring then peppers in summer then garlic in fall; year 3 brassica plus allium in spring then cucurbit in summer then kale plus scallion in fall. The legume year fixes nitrogen for the heavy feeder year that follows. Penn State Extension and Cornell Cooperative Extension both recommend the 3-year minimum.

When should I plant garlic for next summer?

UMN Extension recommends planting garlic 6 to 8 weeks before the ground freezes, usually mid-October to early November in most of the US. Plant individual cloves 4 to 6 inches deep, pointed end up, in rows 8 inches apart. The garlic establishes root systems before dormancy and resumes growth in early spring, harvesting in July or August.

Do cover crops count as companion plants?

Yes, in the broadest sense. A fall-sown cover crop like winter rye plus hairy vetch shares the bed with overwintering garlic, feeds the soil with biomass and fixed nitrogen, suppresses weeds, and prevents winter soil erosion. The vetch follows the rye trellis the same way pole beans climb a corn stalk in the Three Sisters. USDA SARE's Managing Cover Crops Profitably documents the practice in detail.

Resources

• Penn State Extension, Cool-season vs Warm-season Vegetables
• Penn State Extension, Maximizing Your Vegetable Garden
• Penn State Extension, Season Extenders and Growing Fall Vegetables
• Penn State Extension, Plant Rotation in the Garden Based on Plant Families
• UMN Extension, Companion Planting in Home Gardens
• UMN Extension, Cover Crop Selection for Vegetable Growers
• UMN Extension, Tips for Garlic Planting Season
• Iowa State Extension, Soil Temperature and Planting Conditions for Spring
• Iowa State Extension, Planting and Harvesting Your Vegetable Garden
• Cornell Cooperative Extension, Creating a Three Sisters Garden
• Cornell Cooperative Extension, Cool Season Vegetables (PDF)
• Cornell Cooperative Extension, Companion Planting and Flower Borders
• Cornell Garden-Based Learning, Vegetable Growing Guides
• UMD Extension, Vegetable Planting Calendar
• UMD Extension, Growing Garlic in a Home Garden
• Oregon State Extension, Monthly Garden Calendars
• Illinois Extension, Vegetable Succession Planting Chart (PDF)
• University of Delaware Extension, The New Companion Planting: Adding Diversity
• USDA SARE, Selecting the Best Cover Crops for Your Farm
• USDA NRCS, Cereal Rye Cover Crop Fact Sheet (PDF)
• USDA NRCS, Hairy Vetch Cover Crop Fact Sheet (PDF)
• USDA NRCS, Crimson Clover Cover Crop Fact Sheet (PDF)
• USDA NAL, The Three Sisters of Indigenous American Agriculture
• People and Nature 2024, Yield and Labour Demands of Maize, Beans and Squash (peer-reviewed)
• Ethnobiology Letters, Food Yields and Nutrient Analyses of the Three Sisters (peer-reviewed)
• PMC5746795, Companion Plants for Aphid Pest Management (peer-reviewed)
• PubMed 27860184, Calendula officinalis as a Floral Resource (peer-reviewed)
• PMC10245104, Legume Rotation Yield and Nitrogen Uptake (peer-reviewed)