Month-by-Month Companion Planting Planner

Planning ahead is the secret to a productive, pest-resistant allotment. With this month-by-month companion planting planner, you’ll know exactly what to sow together and when, helping you get the most from every season.

Why Plan Companion Planting by Month?

Every crop has its own ideal planting window, and pairing the right plants at the right time can mean healthier growth, fewer pests, and bigger harvests. This planner takes the guesswork out of what to plant together each month.

March

• Peas & Carrots: Sow together for mutual benefit—peas fix nitrogen, which carrots love, and carrots help shade pea roots.
• Onions & Lettuce: Onions deter aphids and other pests from tender lettuce leaves.

Tip: Start marigolds indoors now to plant out as companions in late spring.

April

• Spinach & Radishes: Radishes help break up the soil for shallow-rooted spinach.
• Potatoes & Beans: Beans add nitrogen to the soil, boosting potato growth.

Tip: Interplant chives among your salad crops for early slug defence.

May

• Tomatoes, Basil & Marigolds: Plant together for a classic Mediterranean combo—basil improves tomato flavour, marigolds deter whitefly.
• Sweetcorn & Beans: Beans climb up corn stalks and fix nitrogen for both crops.

June

• Cabbage & Celery: Celery helps confuse cabbage root fly and other pests.
• Courgette & Nasturtium: Nasturtiums attract aphids away from courgettes and provide edible flowers.

July

• Leeks & Carrots: Alternate rows for mutual pest protection.
• Beetroot & Lettuce: Lettuce shades the soil, keeping beetroot roots cool.

August

• Kale & Dill: Dill attracts beneficial insects that protect kale from pests.
• French Beans & Sweetcorn: Continue to support each other through late summer.

September

• Turnips & Peas: Late sowings of both can help fill gaps and improve soil for next year.
• Spinach & Radishes: A repeat of spring’s successful combo.

Tips for Rotating Crops and Adjusting for UK Weather

• Always rotate families (brassicas, legumes, roots, etc.) to prevent disease build-up.
• Adjust sowing dates if the season is unusually warm, cold, or wet.
• Keep an eye on your local forecast and be flexible—gardening is all about adapting!

Conclusion & Free Monthly Reminders

By following this planner, you’ll not only get healthier crops but also make your allotment more resilient to pests and diseases. Want monthly reminders and exclusive planting tips?

For more vegetable pairings and to maximize your allotment space, check out our Companion Planting Chart: The Best Vegetable Pairings for Allotments.

Struggling with slugs? Read our Ultimate Guide to Companion Planting for Slug Control for natural, chemical-free solutions.

⭐ Recommended Products — Garden & Allotment Essentials for March

March is when the growing season truly begins. Seeds are being sown daily, beds are prepared and late frosts are still possible — these essentials help produce strong plants and a successful start.

Seed Trays, Modules & Propagation Kits — perfect for tomatoes, brassicas, lettuce, onions and flowers. 👉 Click here to see top options

Heated Propagators, Heat Mats & Grow Lights — improves germination and prevents leggy seedlings during cold nights. 👉 Click here to see top options

Seed & Cutting Compost — essential for healthy seedlings and strong root growth. 👉 Click here to see top options

Garden Fleece & Plant Protection Covers — protects seedlings, potatoes and early plantings from late frost. 👉 Click here to see top options

Spring Vegetable Seeds — carrots, beetroot, peas, spinach and salads can all be started now. 👉 Click here to see top options

Garden Kneeler & Seat — makes long sowing and planting sessions far more comfortable. 👉 Click here to see top options

Pressure Washer (Greenhouse & Patio Cleaning) — clean patios, paths and greenhouses before planting. 👉 Click here to see top options

Solar Garden Lights — perfect for enjoying the garden during brighter spring evenings. 👉 Click here to see top options