Companion Planting for Cannabis: Marigolds, Basil, Clover — What to Skip

Companion planting for cannabis is growing other plants next to your crop on purpose. Not because a chart on the internet said basil “boosts terpenes.” Not because a marigold is a magic wall. You put a second species in the bed to do a job: slow a pest, feed the insects that eat that pest, cover bare dirt, or fix a little nitrogen over a season. The cannabis still needs light, air, water, and a grower who looks under leaves. If you skip the looking, the companions will not save you.

This page is the working version of that idea. What companion planting for cannabis actually does. What it will not do. Which plants earn a place next to a cola and which ones steal water, shade the canopy, or turn into a pest nursery. How to lay a bed out outdoors. What belongs in a tent and what does not. The four buckets that matter: plants that help, plants to skip, spacing, and trap crops you have to inspect. Genetics still do most of the yield work. Shop: cannabis seeds store. Outdoor seed pick: best cannabis seeds for outdoor growing.

What Companion Planting for Cannabis Actually Is

Farmers have mixed crops for thousands of years. Corn, beans, and squash. Onions next to carrots. The point was never a pretty Instagram bed. The point was one plant covering a job another plant was bad at. Cannabis is a heavy, smelly, pest-attracting annual. A yard of nothing but cannabis is a buffet with one item on the menu. Aphids, mites, whiteflies, and caterpillars find it fast. A mixed bed is harder to hunt in, and it gives predatory insects a reason to stay after the first flush of pests is gone.

That is polyculture. You are not making a forest. You are putting a few well-chosen species in the right spots so the cannabis still gets sun, air, and root room. Companion planting for cannabis is almost always an outdoor and greenhouse job. A 4×4 tent is a sealed box with a humidity budget. Stuffing it with herbs is how you grow mildew. Outdoors, you have soil life, wind, and a real insect community. That is where this technique pays.

A companion is not a pesticide. It is not a fertilizer bottle. It is not a carbon filter. Treat it as support inside a real integrated pest management plan: sanitation, scouting, airflow, plant health, then a targeted spray or a bag of ladybugs when numbers climb. Full outdoor method: growing cannabis outdoors. Soil that can actually hold a living mix: the best soil for growing cannabis.

What Companion Planting Will Not Do

It will not make the garden pest-proof. Growers who plant a ring of marigolds and stop looking under fan leaves find out in week three of flower. Mites do not read garden blogs. A sticky underside and a dusty look on the top of the leaf still mean mites. Companions might slow the first landing. They do not replace a weekly walk with a jeweler’s loupe. Mite page: cannabis and spider mites.

It will not reliably raise terpenes. You will see that claim everywhere. Basil next to cannabis, yarrow “stimulating essential oils,” chamomile “improving flavor.” Cannabis aroma is genetics, plant health, light, harvest timing, dry, and cure. A pot of basil smells like basil. That is not the same as your cola testing higher in limonene. If you want better smell, pick the right seed and do not wreck the dry. Terpenes: enhanced terpenes in cannabis. Seed choice: how to pick cannabis seeds.

It will not hide a flowering plant from a neighbor. Lavender and basil add garden smell. A ripe sativa in August still throws. If stealth is the job, you need distance, a greenhouse, or an indoor tent with a filter — not a herb border. Indoor: indoor cannabis growers guide. Tent: grow tent.

It will not feed a hungry plant by itself. Clover fixes nitrogen in its own roots. That nitrogen does not jump into your cannabis the week you sow the seed. You still build soil, you still water right, you still watch for lockout. Yellowing is still a diagnosis, not a reason to sow more clover. Nutrients: cannabis nutrient deficiency. Organic feed: organic marijuana fertilizer.

The Four Jobs Companions Actually Have

Every plant you add should have one of these jobs. If it does not, it is a roommate who pays no rent.

• Diversity. A solid block of cannabis is easy to find. Mixed height, mixed scent, and mixed leaf shape make it harder for some pests to lock onto a host. That is not invisibility. It is friction.
• Food and housing for predators. Ladybugs, lacewings, hoverflies, and tiny parasitic wasps need nectar and pollen. Yarrow, dill, cilantro, alyssum, and flowering basil give them a reason to stay. Predators: using beneficial insects in your cannabis garden.
• Living mulch and soil cover. Bare dirt crusts, cooks roots, and invites weeds. Low clover or a chopped cover crop shades the surface, holds moisture, and feeds microbes as it dies. Organic soil: organic cannabis soil.
• A few real chemical jobs. French marigold roots make thiophenes that can suppress some root-knot nematodes. Alliums and strong herbs add scent that may confuse a portion of flying pests. None of that is a label rate. It is a nudge.

Pick the job first. Then pick the plant. A backyard with mite pressure wants predators and airflow, not a wall of mint. A sandy bed with nematodes wants Tagetes on the perimeter, not a sunflower. A 20-gallon fabric pot already fighting for water does not want a clover mat on top of the same root ball.

Best Companion Plants for Cannabis

The useful list is short. Marigolds, basil, nasturtiums (as a trap you inspect), yarrow, dill, cilantro, clover in the ground, garlic and chives, and a couple of woody herbs in their own pots. That is enough. You do not need twenty species. You need three or four that fit the bed, the climate, and the pest you actually have.

Marigolds: perimeter, nematodes, whitefly

Use Tagetes. French marigold (Tagetes patula) and African marigold (Tagetes erecta). Not calendula, even if the seed rack calls it a marigold. The root chemistry people talk about — alpha-terthienyl and related thiophenes — lives in Tagetes. Those compounds can suppress some root-knot nematodes when the plants are in the ground long enough for the roots to occupy the soil. That is a soil job. It is not a spray for mites on a cola.

Plant them as a border, not as a skirt jammed against the stem. A ring around the bed, or a line along the path where you walk and look. Give the cannabis the middle. Marigolds stay compact if you pinch spent blooms. If they stretch into the lower branches, cut them back. Stale air under a cola in August is how you grow bud rot, and a pretty flower is not worth a grey cola.

Whitefly pressure is the other reason people plant them. The scent and the extra flowers can help a mixed garden. They will not erase a greenhouse whitefly bloom. If you see clouds when you shake a leaf, you are in IPM, not in marigold country. Outdoor pest list: preventing fungi and pests in outdoor cannabis.

Signet marigolds are edible and cute. They are a weak nematode tool. If nematodes are why you bought the pack, buy French or African and plant them into the soil you will use, not into a six-inch pot on the deck.

Basil: interplant for aphids and thrips

Basil is the companion you can actually use in a small yard. It stays manageable. It likes heat and regular water, same as cannabis in summer. The scent is strong. Extension work on tomatoes has shown basil can reduce thrips in some systems. Aphids also seem less happy on a mixed basil-and-crop planting than on a clean monoculture. That is a maybe with a track record, not a guarantee. Aphids: aphids on cannabis plants.

Put basil in its own pot next to the cannabis, or in the same in-ground bed a foot or more off the stem. Do not drop four basil plants into a 10-gallon fabric pot with a photoperiod. The pot does not have the water or the root room. A 3-gallon basil pot you can move is better than a roommate in the same bag.

Pinch basil so it stays bushy. If you want hoverflies, let a few stems flower. If you want pesto, keep pinching. Either use is honest. The dishonest use is “basil makes the bud taste better.” It makes the garden smell like basil. The bud still tastes like the seed you popped and the dry you ran.

Sweet basil, Genovese, Thai, and lemon basil all work as companions. Lemon basil is a nicer indoor-adjacent plant because the scent is sharp. None of them like a cold snap. In a short northern summer, start basil inside and set it out after the last frost with the cannabis, not two months later when the crop is already in flower.

Nasturtiums are a trap crop, not a shield

Nasturtiums grow fast, trail, and aphids love them. That is the point. A trap crop is a plant you grow so the pest lands there first. You then look at it, and you do something. Pinch the infested stems. Throw a bad plant in a bag. Hit that pot with soap. If you plant nasturtiums and never look at them, you built an aphid factory at the edge of the cannabis. That is the failure mode ranking pages skip.

Keep them at the edge of the bed or in a hanging pot you can pull away. Trailing types will crawl under the canopy if you let them. That blocks air. Air is worth more than a trap crop. Do not let nasturtium vines knit into the lower branches in late flower.

The flowers and leaves are edible. That is a bonus, not the job. The job is inspection. Walk the nasturtiums every time you walk the cannabis. If they are clean and the cannabis is clean, leave them. If they are coated and the cannabis is still clean, you are winning — until you stop looking.

Yarrow, dill, and cilantro for predators

Predators do not live on vibes. Tiny wasps that parasitize aphids need small, open flowers. Hoverflies need the same. Lacewings and ladybugs use pollen and nectar when prey is thin. Yarrow, dill, cilantro, parsley left to flower, and sweet alyssum are the cheap way to keep that cafeteria open.

Yarrow is a perennial with a deep root. It can mine minerals and then drop them as mulch when you cut it. Plant it at the back of the bed or along a fence, not in a 15-gallon pot with the cannabis. It spreads. Give it a corner. Dill and cilantro bolt in heat. That is useful. Sow a pinch every two or three weeks so something is always flowering. When a patch goes to seed, cut it and drop the stems on the soil as mulch if they are clean, or compost them if they are not.

Do not plant fennel for this job. Fennel is in the same family as dill and it looks like a predator plant. It is also allelopathic — it leaks compounds that stall neighbors. Keep fennel out of the cannabis bed. Dill stays. Fennel goes to the far side of the yard or not at all.

Clover as living mulch, not a bottle of nitrogen

Clover is a legume. Rhizobium bacteria in the nodules take nitrogen from air and lock it in the plant. When roots and leaves die, some of that nitrogen becomes available to whatever is next to them. That is slow. It is not a tea you pour in week two of flower. If the cannabis is hungry now, clover will not catch it up. Feed the plant. Build the soil for next year with the clover.

White clover and microclover stay low. Red clover grows taller and is a better plow-down or chop-and-drop in a bed you will replant. In the ground, a thin clover carpet between plants is one of the best companions you can run: it shades soil, cuts splash, holds moisture, and gives bees something to do. In a small pot it is a competitor. A 5-gallon or 10-gallon container already has a limited water and root budget. A dense clover mat in that pot will drink and shade the surface while the cannabis is trying to establish. If you want cover in a pot, keep it sparse, trim it, or skip it and use straw.

Do not let clover climb into the lower bud sites. Mow or shear it when it gets ambitious. A living mulch that stays under a hand high is a mulch. A living mulch that hits the cola is a humidity blanket.

Garlic, chives, and onions

Alliums earn a border row. Garlic, chives, and bunching onions take little space, throw a sulfur smell, and do not shade a cannabis plant. Some growers plant garlic cloves in fall around a bed they will fill in spring. Chives come back every year. None of them replace a spray. They add scent diversity and they give you food.

Keep the bulbs in a strip at the front of the bed, not in the same hole as the cannabis. Garlic wants a drier shoulder than a flowering cannabis plant in a wet August. If you water the cannabis daily, the garlic in that same circle may rot. Separate irrigation is the whole reason a border works.

Lavender, lemon balm, rosemary, and thyme

These are the “mask the smell” plants on every list. They smell. Flowering cannabis still smells more. Use them for bees and for a garden that does not look like a single crop, not as a stealth plan.

Lavender wants sharp drainage and hates wet feet. Cannabis in flower wants regular water. Put lavender in its own pot or on a dry berm, not in the same soil you keep moist for a 6-foot plant. Rosemary and thyme are the same story: woody, drier, slower. Lemon balm is a mint relative. It spreads. Pot it. Chamomile is a small annual or a low perennial depending on the type. It can sit at the edge. It will not change your resin glands.

Lemongrass shows up on tropical lists because it bothers mosquitoes. In a short-season climate it is a patio pot you drag inside, not a field companion. If you can overwinter it, fine. If you cannot, skip it and spend the space on basil and marigolds.

Mint Belongs in a Pot

Mint, peppermint, spearmint, and lemon balm will take a bed. They run by rhizomes. A year later you are pulling mint out of the cannabis root ball. The scent does bother some ants and some flying pests. That is not worth an infestation of mint. Plant it in a terracotta or fabric pot. Set the pot next to the cannabis. Water the mint separately. If it gets mites, you throw the pot, not the crop.

Catnip is in the same family. Same rule. Same pot. Do not put any of these in the ground next to a perennial bed you like unless you want that bed to become mint.

What You Should Not Plant Around Cannabis

The skip list matters as much as the plant list. Ranking pages that only sell “best companions” leave you with fennel under a cola and a sunflower on the south side. That is how you grow a shaded, stalled crop.

Fennel

Fennel leaks allelochemicals that stall a lot of neighbors. It looks like dill, so people plant it for hoverflies. Plant dill instead. Keep fennel in its own corner of the yard, or skip it.

Black walnut and juglone

Black walnut trees drop juglone into soil and leaf litter. A lot of crops hate it. Cannabis is not a walnut companion. Do not site an in-ground bed under a walnut. Do not mulch with walnut chips. A fabric pot on a patio 30 feet away is a different problem. A bed in the drip line is the problem.

Sunflowers on the sun side

Sunflowers pull pollinators. They also get tall, they shade, and some types are allelopathic. A row on the north fence as a screen can work. A row on the south side of a cannabis plant in a short season is a light thief. Cannabis wants the sun. Give the sunflower a different job, farther away. If you want height for a screen, use a fence.

Brassicas, mustard, and cabbage-family magnets

Mustard, broccoli, kale, and cabbage pull aphids, flea beetles, and cabbage loopers. Some of those pests will sample cannabis once they are in the yard. A mustard cover crop you till in before veg is a soil tool. A mustard plant in full flower next to a cola in July is a pest taxi. Keep brassicas in their own row with space between, or run mustard as a cover you kill before the cannabis goes in.

Cucumbers, squash, and mildew houses

Cucurbits bring spider mites, cucumber beetles, and powdery mildew. They also sprawl and hold humidity. A zucchini under a flowering cannabis plant is a wet cave. Grow the squash in another bed. If the yard is tiny, grow the squash in a pot on the other side of the path. Mites move. Do not build them a bridge.

Old field charts also warn you off cotton and sorghum. You are probably not growing those next to a patio plant. The useful version: do not copy a farm list into a backyard. Skip plants that share the worst cannabis pests, skip plants that shade, skip plants that want a different water schedule in the same hole. The plant that wrecks the most gardens is not fennel. It is “one more companion.” If a stem is touching a cola, it is in the wrong place. Stake and open the crop: strengthen cannabis branches and stems.

Outdoor Layout: Perimeter, Interplant, Living Mulch

Think in three rings, not a jumble.

The crop in the middle. Cannabis gets the sun, the biggest pot or the deepest soil, and a walkable gap around it. You should be able to circle the plant without wading through herbs. That gap is where you look at stems, where you water, and where air moves. Pot size and watering change the whole picture: environment, media, watering, and pot sizes.

The interplant ring. Basil, chives, a compact marigold, maybe a parsley. These sit a foot or more off the stem in ground, or in their own pots on the same saucer line. They are close enough for scent and for you to see them when you scout the crop. They are not in the drip crater you flood twice a week in August.

The perimeter. Marigolds, nasturtiums you will inspect, yarrow, dill, a lavender in its own pot, garlic in a strip. This is the insect cafeteria and the nematode border. It is also the place a trap crop can sit without dripping aphids onto a cola.

Living mulch goes on the soil, not up the plant. Clover, or a chopped cover, or straw. Keep it low. Water the cannabis at the stem or with a drip line under the mulch, not with a sprinkler that soaks every flower. Watering: how to water cannabis plants.

Sun angle matters. Put the short plants on the south and west so they do not shade the crop in a short season. Put the yarrow and any taller herb north of the cannabis. If you need a privacy screen, that is a fence or a hedge away from the root zone, not a sunflower glued to the pot.

Deer do not care about basil. If deer are the pest, companions are not the tool. Fence, cages, and the usual ugly tricks: keeping deer away from your cannabis garden. Slugs and snails like a wet mulch and a dense herb ring. If you run clover in a wet climate, check the stems at night. Slugs: slugs and snails off cannabis plants. Grasshoppers will chew nasturtiums and cannabis. A trap crop will not stop a hopper year. Grasshoppers: grasshoppers eating marijuana.

Start companions when you start the bed, not in week five of flower. Marigolds and basil need weeks to do anything. A nematode border planted in August is decoration. Sow or transplant at the same time you set the cannabis out, or earlier. Outdoor plants still have to finish before frost. Pick seed that matches the season: best cannabis seeds for outdoor growing.

Indoor Companion Planting in a Tent

A tent is not a garden. It is a box you already struggle to keep in range for temperature, humidity, and smell. Every extra plant transpires. Every extra pot is a place fungus gnats breed. Every extra stem is a place mites hitchhike from the hardware-store basil you did not quarantine.

If you run companions indoors, run one small pot of basil or chives at the edge of the tent, on its own saucer, that you can yank in five seconds. Do not fill the floor with marigolds. Do not put mint in the tent. Do not put a nasturtium trap crop under a 600-watt light and then forget it. Indoor pests have nowhere to go but the cannabis.

Quarantine is the indoor version of companion planting that people skip. New herbs from a grocery store or a garden center are a common mite and thrips delivery. Bag them or keep them in another room for a week and look with a loupe before they share air with the crop. Thrips ride basil. Mites ride almost anything.

Humidity is the indoor tax. A basil plant in veg at 60 percent RH is fine. The same basil in late flower when you are trying to sit at 45 percent is a humidifier you did not ask for. Pull companions before the last two weeks if the tent is climbing. Ventilation: ventilation for cannabis grow. Environment: best growing environment for cannabis. Room build: building the grow room.

Hydro and coco trays are the wrong place for clover. There is no soil food web to join, and the cover will clog emitters and hide fungus gnat larvae. Living mulch is a soil-bed tool. In a tent, a clean surface you can see is worth more than a pretty cover.

Neem trees as bonsai show up on indoor lists. That is a novelty, not a pest program. If you want neem, use a labeled oil on a schedule you understand, not a tree in the corner. Neem: cannabis pests with neem oil.

Cover Crops, Chop-and-Drop, and Nitrogen

Cover crops are companions with a calendar. You sow them to occupy soil, then you kill them before they become a weed. Buckwheat is fast, smothers ground, and flowers for hoverflies if you let it. Peas and beans fix nitrogen and can be chopped at the soil line. Clover we already covered. A mixed “soil builder” pack is fine in a bed you will plant into next month. It is a mess in a 20-gallon pot with a plant already in it.

Chop-and-drop means you cut the cover at the soil and leave the stems as mulch. Do it before the cover sets seed unless you want that cover forever. Do it before the cover outgrows the cannabis. A buckwheat patch in full flower is a bee magnet and a light thief. Cut it when it is knee high and let the roots rot in place. That is organic matter. That is the soil job. Organic soil: organic cannabis soil. Amendments: organic marijuana fertilizer.

A chopped clover sward will not replace a flower feed on a plant that is already yellow. Diagnose the leaf, then act. Comfrey (Bocking 14 if you do not want it to seed) can sit at the edge of a bed as a cut-and-mulch plant. Keep it in its own hole. It will shade a short auto if you baby it next to the stem.

Spacing, Water, Humidity, and Bud Rot

Companion planting fails most often as a crowding problem, not as a “wrong species” problem. Cannabis in flower wants dry air around the colas and wet enough soil at the roots. Herbs want to be close. Those two wants fight.

Leave a walkable gap. If you cannot get a hand and a loupe to the middle of the plant, you planted too tight. Trim companions the way you would tuck a fan leaf — because they are in the way. In late flower, be ruthless. A marigold that touched a cola last week and is still touching it this week is a rot risk in a wet climate. Bud rot: cannabis bud rot. Outdoor fungi: preventing fungi and pests outdoors.

Water on two schedules if the plants disagree. Basil in a 3-gallon pot on a hot slab may need water daily. A 30-gallon cannabis pot may not. A clover carpet may hide a dry pot because the surface still looks green. Lift pots. Use a meter if you like. Do not assume the companion’s leaves mean the cannabis is watered. Watering: how to water cannabis plants.

Feed on the cannabis schedule, not the basil schedule. Herbs in their own pots get their own bottle or their own compost. If they share a bed, remember cannabis in flower wants a different N-P-K than a basil plant you keep in veg forever. Shared soil is a compromise. Separate pots are how you stop compromising.

Yield does not come from the marigold. Yield comes from a plant that kept its leaves, kept its roots, and kept its colas dry enough to finish. Companions help by making that easier, or they hurt by making it wetter and shadier. If the bed looks like a jungle, you already chose the second option. Yield: increase cannabis yields.

A First-Year Companion Plan You Can Run

Do not start with twelve species. Start with a layout you will actually maintain.

In-ground or a raised bed. One to four cannabis plants with real spacing. A French marigold border on the path side. Two basil plants in 2- or 3-gallon pots you can move. A thin white clover or microclover on the bare soil, sheared when it climbs. One nasturtium at the far corner that you inspect every time you water. A strip of chives or garlic at the front. That is a complete companion planting for cannabis in year one.

Containers on a deck. Cannabis in its own fabric pots. Basil in its own terracotta. Marigolds in a window box along the rail, not in the cannabis pot. No clover in a 10-gallon. No mint in the ground — there is no ground, which is the point. If a herb gets mites, it leaves the deck.

Greenhouse. Fewer companions than outdoors, more than a tent. Airflow is the limit. Marigolds and basil at the ends of benches. No dense clover under benches where you cannot see fungus gnats. Open the house. Scout the undersides. A greenhouse is a pest incubator if you pack it.

Tent. One basil or nothing. Quarantine anything that comes in. Pull the basil if RH climbs in late flower. The tent’s job is the crop. Environment: best growing environment.

Week one of the plan is not planting. It is walking. Look at new growth, undersides, soil surface, and the trap crop. Sticky residue, stippling, webbing, chewed holes, slime trails — write them down. Companions only help a grower who is already looking. If you will not look, skip the herbs and spend the money on a loupe and a fan.

When Companions Fail and You Still Need IPM

Companions failed when the aphids are on the cannabis, not just on the nasturtium. They failed when mites are webbing a cola. They failed when a caterpillar is in the flower and the yarrow is blooming like nothing happened. That is the moment you stop arguing for the herb border and you treat the crop.

IPM is still the stack: sanitation, scouting, environment, biology, then a spray with a target. Soap, oil, Beauveria, predatory mites, Bt for caterpillars — pick the tool that matches the pest. Neem is a tool, not a personality. Beneficial insects work better in a mixed outdoor bed than in a sealed tent, which is one honest reason companion planting and predator releases go together outdoors. IPM: integrated pest management for cannabis. Beneficials: beneficial insects in your cannabis garden. Neem: neem oil.

If the same companion is always covered in pests, and those pests keep jumping, move it or kill it. A trap crop you cannot keep up with is a reservoir. If the cannabis is pale, do not sow more clover. Read the leaf. Check water, salt, and pH. Deficiency: cannabis nutrient deficiency. Harvest still follows genetics, light, and a finish that did not rot. Pick the seed for the space, then build the bed around it.

How to Scout a Mixed Cannabis Bed

A companion bed that you do not scout is just a crowded bed. The walk is the method. Same days each week. Morning is easier because flying pests are slower and dew shows damage. You are not meditating. You are looking for numbers.

Start at the trap crop. If the nasturtium is clean, note it. If it is peppered with aphids, that is your early warning, not a reason to panic — unless the cannabis already has them too. Then move to the cannabis: newest growth, undersides of interior fans, stem crotches, and the tops of colas once you are in flower. Then the soil line for fungus gnats, slugs, and cutworms. Then the perimeter flowers for the predators you actually have, not the ones the seed packet promised.

A jeweler’s loupe or a cheap clip-on phone scope pays for itself the first time you see mite eggs instead of “dust.” Yellow sticky cards at the edge of a greenhouse tell you when whitefly or fungus gnats are moving. They do not replace the walk. They give you a trend.

Write one line. “July 12, nasturtium aphids, cannabis clean, two ladybugs on yarrow.” Next week you know if the trap is working or if you are losing. Companion planting without notes is how people swear marigolds “do nothing” after a year they never measured.

Containers, Raised Beds, and In-Ground — Different Rules

The same plant list does not fit every vessel. In-ground soil can hold clover, garlic, and a marigold border without starving a deep-rooted cannabis plant. A raised bed is similar if it is deep and you do not pack it. A fabric pot is a closed budget. Treat it like a tent floor: companions get their own pots.

In-ground: plant the cannabis, then seed clover in the alleys, then set marigolds on the path, then set basil a step off the stem. Water the crop at the base. The clover can live on what it gets. If a dry week hits, the cannabis still gets the can.

Raised bed: same layout, watch the edges. Beds dry from the sides. Herbs on the rim may crisp while the middle is still wet. That is fine for thyme. It is not fine if your only basil is on the rim and you are using it as the aphid plant.

Fabric pots and grow bags: one plant per bag unless the bag is huge and you know what you are doing. A 30- or 45-gallon no-till pot can hold a sparse cover. A 7-gallon cannot. Set companion pots on the same tray so you remember they exist, then water them on their own day. Environment and pot size: pot sizes and watering.

Season Timing: When to Sow, When to Pull

Companions that start late do no work. Marigolds you transplant in week four of flower will not build a nematode-active root system in time. Basil you seed in July in a northern yard may not outrun the cannabis. Match the companion to the crop calendar.

Spring: start basil and marigolds inside with the cannabis or buy stocky transplants. Sow clover when you can keep it moist. Garlic, if you use it, was planted last fall. Chives are already up if you had them.

Early veg: set the border. Set the basil pots. Let clover fill. This is when diversity starts to matter, because pests are also moving into the yard.

Stretch and early flower: pinch basil, deadhead marigolds, shear clover, pull any vine out of the lower canopy. This is the last easy window to rearrange pots without snapping a cola.

Late flower: air wins. Pull anything that touches a bud. Pull indoor basil if RH is high. Stop watering the clover into the colas with a sprinkler. If a trap crop is a mess, bag it. You are protecting the finish, not the herb garden.

After harvest: leave the clover and the perennials. Chop annuals that are diseased. Compost clean stems. Next year’s nematode border is easier if the Tagetes roots already lived in that soil once. Next year’s yarrow is already in the fence line. That is the long game. One season of marigolds is a trial. Three seasons of a stable border is a system.

Most lists recycle the same line: marigold, basil, lavender, clover, “enhances terpenes,” “masks odor,” “repels all pests.” Some of those plants belong. Most of those claims do not. Companions support IPM. Trap crops need inspection. Mint stays in a pot. Clover competes in small containers. Fennel and walnut are out. Crowding is a bud-rot risk. Indoor herbs add humidity. Basil is not a terpene additive. Build a bed you can walk. Plant three companions you will actually maintain. Scout. Pull what fails. Keep the cannabis in the sun and in the air. That is companion planting for cannabis. It is not the whole grow. Store: cannabis seeds store. Outdoor: growing cannabis outdoors.