Plant These 10 Crops in March to Cut Pesticide Use

Plant These 10 Pest-Repelling Crops in March to Reduce Pesticide Sprays

If you want to cut back on chemical pesticide sprays this season, plant these 10 crops in March: calendula, sweet alyssum, dill, cilantro, chives, nasturtium, marigold, borage, yarrow, and garlic chives. These plants attract lady beetles, lacewings, hoverflies, parasitic wasps, and pollinators that naturally suppress aphids, whiteflies, cabbage worms, and flea beetles. They also confuse or deter some pests through scent and mixed planting. The result is fewer spray purchases, less crop damage, and lower risk of killing beneficial insects with broad-spectrum pesticides.

Quick-Start March Planting Checklist

1. Check your USDA zone and last frost date. In zones 3–5, start seeds indoors 4–6 weeks before last frost or sow under row cover. In zones 6–8, direct sow once soil is workable and at least 45–50°F.
2. Prepare beds. Loosen soil 6–8 inches deep, remove weeds, and add compost if needed.
3. Sow cool-season flowers and herbs. Plant calendula, sweet alyssum, dill, cilantro, chives, nasturtium, marigold, borage, yarrow, and garlic chives at the depths and spacings listed below.
4. Use row covers in cold zones. Protect early sowings from frost and wind while allowing light and water through.
5. Succession sow every 2–3 weeks. Stagger plantings of cilantro, dill, and calendula for continuous blooms and beneficial insect support.
6. Monitor and manage trap crops. Check nasturtiums regularly for aphids and prune or hot-compost heavily infested growth.

Calendula

Calendula is one of the most useful March flowers for vegetable beds. It tolerates cool weather, flowers over a long season, and attracts hoverflies and parasitic wasps whose larvae or offspring help control aphids and other soft-bodied pests. Sow seeds about 1/4 inch deep and thin plants to 8 to 12 inches apart.

Best for: vegetable borders, raised beds, orchard edges, and cool spring climates.

Not suitable for: waterlogged soil or sites where self-sowing is unwanted.

Companion pairings: Plant near tomatoes, lettuce, and brassicas to draw in aphid predators.

Sweet Alyssum

Sweet alyssum is a low-growing annual that produces many small flowers attractive to hoverflies and tiny parasitic wasps. It works well along bed edges because it does not usually shade vegetables. Scatter seed thinly, press it into the soil surface, and keep it moist for 7 to 14 days while it germinates.

Best for: edging lettuce, brassicas, carrots, onions, and greenhouse paths.

Not suitable for: very hot, dry positions unless irrigated 1 to 2 times per week during dry spells.

Companion pairings: Use as living mulch around cabbage and broccoli to support parasitic wasps.

Dill

Dill supports beneficial insects when allowed to flower. Its umbrella-shaped blooms are especially useful for small wasps, hoverflies, and other predators that need exposed nectar sources. Sow seed 1/4 inch deep and space plants 6 to 12 inches apart; a short row every 3 weeks keeps flowers coming.

Best for: planting near cabbage, kale, broccoli, cucumbers, and tomatoes.

Not suitable for: tight spacing near carrots if you want to avoid confusion with similar seedlings or accidental cross-management of related crops.

Companion pairings: Pair with brassicas and cucumbers to boost natural pest control.

Cilantro (Coriander)

Cilantro, also called coriander when grown for seed, is useful in March because it prefers cool weather and bolts quickly as temperatures rise. Once flowering, it becomes a strong beneficial-insect plant rather than just a culinary herb. Sow 1/4 to 1/2 inch deep and harvest leaves when plants are 4 to 6 inches tall.

Best for: succession sowing every 2 to 3 weeks in spring.

Not suitable for: gardeners expecting long leaf harvests in hot weather above about 75°F.

Companion pairings: Sow between spinach and lettuce to attract hoverflies during cool weather.

Chives

Chives are perennial alliums with edible leaves and purple flowers that attract pollinators. Their onion scent may help confuse some pests when planted near carrots, lettuce, and brassicas, though they should be treated as support plants rather than a guaranteed repellent. Plant clumps 8 to 12 inches apart, or keep 1 plant in a 6- to 8-inch pot.

Best for: permanent bed edges, containers, and low-maintenance herb patches.

Not suitable for: deeply shaded beds or gardens where allium family plants are being avoided for crop rotation reasons.

Companion pairings: Place near carrots and lettuce to help mask host-plant scents from pests.

Nasturtium

Nasturtium grows quickly from large seeds and is often used as a trap crop for aphids. It can draw aphids away from brassicas and cucurbits, but the infested growth should be pruned out or composted hot if pest numbers build. Sow seeds 1/2 to 1 inch deep and give bush types 10 to 12 inches of space; trailing types may need 2 to 3 feet.

Best for: bed corners, trellises, containers, and sacrificial trap planting.

Companion pairings: Position near cabbage, kale, and cucumbers to lure aphids away from main crops.

Marigold

Marigolds are widely used in vegetable gardens for their strong scent, which can help deter some above-ground pests and may suppress certain soil nematodes when grown densely and tilled into the soil at season’s end. Sow seeds 1/4 inch deep after soil warms to about 60°F, or start indoors 4–6 weeks before last frost in cooler zones. Space plants 8 to 12 inches apart.

Best for: borders of tomato, pepper, and bean beds; interplanting with squash.

Not suitable for: very cool, wet soils where seeds may rot before germinating.

Companion pairings: Plant with tomatoes and peppers to support general pest suppression.

Borage

Borage is a fast-growing annual herb with blue, star-shaped flowers that are highly attractive to bees and parasitic wasps. It can improve pollination of nearby fruiting crops and support generalist predators. Sow seeds 1/4 to 1/2 inch deep and thin or transplant to 12 to 18 inches apart.

Best for: near strawberries, tomatoes, squash, and cucumbers.

Not suitable for: very small containers or crowded beds where its large size may shade smaller crops.

Companion pairings: Pair with squash and cucumbers to boost pollinator visits.

Yarrow

Yarrow is a hardy perennial that produces flat flower clusters attractive to hoverflies, lady beetles, and parasitic wasps. It tolerates poor soil and drought once established, making it useful for low-maintenance pest-management plantings. Sow seeds on the soil surface and press in lightly, or divide existing plants in early spring. Space plants 12 to 24 inches apart.

Best for: perennial borders, orchard edges, and low-water gardens.

Not suitable for: very shady or constantly wet sites.

Companion pairings: Use near fruit trees and berry bushes to support beneficial insects.

Garlic Chives

Garlic chives are perennial alliums with a mild garlic-onion scent and white flowers that attract pollinators and beneficial insects. Like common chives, they can be used around vegetable beds to help confuse some pests with their scent. Plant clumps 8 to 12 inches apart or grow in containers.

Best for: bed edges, herb spirals, and containers.

Not suitable for: deeply shaded beds or gardens avoiding alliums for rotation reasons.

Companion pairings: Place near lettuce, carrots, and brassicas for added pest confusion.

Regional Zone and Timing Tips

March planting timing depends on your climate zone. In USDA zones 3–5, focus on indoor seed starting and early sowings under row cover once soil is no longer frozen. In zones 6–7, direct sow cool-season crops like calendula, sweet alyssum, cilantro, and chives as soon as soil is workable and at least 45–50°F. In zones 8–9, March is ideal for direct sowing most of the listed plants outdoors. Always check local extension service planting calendars for precise dates in your area.

Recommended Tools and Supplies

To get the most from your March pest-repelling plantings, consider these supplies:

• Seed kits: Look for pollinator-friendly or pest-repelling flower seed mixes that include calendula, sweet alyssum, and marigold.
• Row covers: Lightweight floating row covers protect early sowings from frost and wind while allowing light and water through.
• Soil thermometer: Use a soil thermometer to check that soil temperatures are in the right range before sowing (45–50°F for cool-season flowers, 60°F+ for marigolds).
• Compost and mulch: Improve bed structure and moisture retention to help young plants establish quickly.

Sources and Further Reading

For more information on integrated pest management and beneficial-insect plantings, consult your local university extension service or the USDA National Institute of Food and Agriculture. Many extensions publish region-specific planting guides and pest-management recommendations that can help you refine your March planting plan.

The Result

By planting these 10 pest-repelling and beneficial-insect-attracting crops in March, you can reduce your reliance on chemical pesticide sprays, support a healthier garden ecosystem, and protect pollinators and natural pest predators. Use the checklist and companion planting tips above to plan your beds, and adjust timing based on your USDA zone and local conditions.