Your Murdering Your Plants…..
All of us have encountered someone in our lives whom we just couldn’t stand. For some reason they way they walk, talk, laugh, smile…. It just irritates us. They zap us of our energy. Thank goodness for friends, people who energize us and make us feel good about ourselves.
Did you know that plants, like humans, also react negatively to certain plants? Sometimes specific plants can actually kill and prevent the growth of others. Take sunflowers for example. They are beautiful, and a staple in most gardens. That beautiful sunflower… it emits a chemical which prevents the growth of most vegetables and flowers. This chemical can last in the soil and stunt the growth of other plants for years.

Shocked? I was too when I learned about the “evils” of the sunflower. Especially since sunflowers are my favorite flower and I plant them every year. Luckily plants, like humans, also have companions “best friends”. When these plants are planted together they benefit each other. That nasty sunflower. While it hurts most plants, it is good for corn, peas, beans and squash.
The second step for planning your garden (click here for step 1) is going through all of the things you intend to plant this year and find out what plants work well together, and what plants harm/kill each other.
Below is the list I have made for my own garden this year. Once you find out which plants work well together it is time to move on to step 3.
Plant | Plant Near/With | Don’t plant by | When to Plant |
Asparagus | Nightshades, like tomatoes and eggplant, Basil and parsley, Coriander, comfrey, and dill, Members of the Aster family, like marigolds and nasturtiums | Garlic and Onion | 1-May |
Basil | Borage, Chamomile, oregano, chives, marigolds, peppers, root vegtables, tomatoes. | rue, sage | 1-May |
Beet | cruciferous vegetables like kohlrabi, kale, cauliflower, broccoli, and Brussels sprouts | pole beans and mustard | 1-Apr |
Beans | Broccoli, Brussels sprouts, Cabbage, Carrots, Cauliflower, Celery, Kale, Peas. | any member of the onion family. | 1-Jun |
Broccoli | Beets, celery, chamomile, lettuce, potatoes, rhubarb, rosemary, shallots | Nightshades. Tomatoes, eggplants, peppers, cabbage, cauliflower, beans and strawberries | 1-May |
Cabbage | Aromatic herbs: Chamomile, hyssop, thyme, rosemary, dill, peppermint, spearmint, sage, oregano. Garden edging: Yarrow, marigolds. Root vegetables: Onions, beets, celery. | mustard plants, strawberries, tomatoes, grapes and pole beans | |
Cantaloupe | corn, pumpkin, squash, collards, borage, oregano, radishes, marigolds, petunias and beans | cucumbers | 1-Jun |
Carrot | Tomatoes, Leeks, Onion, Rosemary, Sage, Chives, Beans, Amaranth | parsnip, dill and fennel | 1-Apr |
Cauliflower | beans, peas, spinach, celery, sage, dill, and chamomile | strawberries, peas, beans and onion | |
Celtuce | 1-Aug | ||
Corn | beans, beets, cucumber, dill, melons, parsley, peas, potato, soya beans, squash, and sunflower. | tomatoes, cabbage, broccoli, brussel sprouts, kale and cauliflower | 7-May |
Collards | mint, chives and garlic to repel aphids. Beans, beets, broccoli, carrots, corn, peas, radishes, and marigolds also work as good companion plants | soybeans, peas, cucumbers, cabbage, broccoli, beets, beans and asparagus | 1-Apr |
Coriander | Basil, parsley, and chervil. | fruit bearing plants like peppers and tomatoes | 1-May |
Cucumber | corn, dill, legumes, marigolds, Nasturtiums, root vegetables and sunflowers | mellons, potatoes, sage, fennel, kale, kohlarabi, brussel sprouts, cabbage, cauliflower | 1-Jun |
Dill | asparagus, corn, cucumbers, onion, lettuce, Brussels sprouts, kohlrabi, broccoli, basil | caraway, carrots, fennel, nightshades (pepper, tomato, egg plant) | 1-Jun |
Egg Plant | peppers, tomatoes, potatoes and spinach | fennel | 1-Apr |
Gooseberry | beans, Chamomile, chives, kiwi, peas, oragano, Nasturtiums and mint. | tomatoes | Plat indoors in zone 4 |
Ground Cherry | 1-Apr | ||
Kale | beets, celery, cucumbers, herbs, onions, spinach, chard, and potatoes. | broccoli, kohlrabi, cauliflower, brussels sprouts, and Swiss chard | 1-Apr |
Kohlrabi | beets, Brassicas, cucumbers, and onions | peppers, pole beans, strawberries, and tomatoes. Leeks | 1-May |
Lavender | Basil and oregano | 1-Mar | |
Lettuce | beets, carrots, parsnips, strawberries, radishes, onions, asparagus, corn | broccoli, brussels sprouts, cabbage, cauliflower, kale, or kohlrabi | 1-Apr |
Melon | peas, pole beans, bush beans, onions, leeks, chives, and garlic, cabbage, broccoli, cauliflower, carrots, kale, okra, spinach, sunflowers, lettuce, and Brussels sprouts | cucumber, zucchini and other melons | 15-Jun |
Okra | peppers, eggplants, lettuce and melons | Okra should not be planted in soil previously utilized to grow vine crops such as sweet potatoes and squash | 1-Jun |
Onion | lettuce, chammomile, summer savory tomatoes, and herbs such dill, parsley, or mint | Never plant other types of onions near onions. Peas, Beans, Asparagus and sage. | 1-Jun |
Parsley | tomatoes, chives, carrots, corn, peppers, onions and peas. | Alliums, Garlic, Onions, Shallots. Lettuce | 1-May |
Peas | beans, carrots, celery, corn, cucumbers, eggplant, peppers and radishes | onions, garlic, and chives | 1-Apr |
Pepper | Carrots, cucumbers, radishes, squash, spinach, lettuce and chard. | beans, Brassicas, onion or fennel | 1-Apr |
Pumpkin | beans, corn, sunflowers, marjoram, marigolds, Nasturtiums, lavendar | root crops, such as beets, onions, and potatoes | 1-Jun |
Radish | lettuce, spinach, squash, parsnips, beans, chervil, peas, nasturtimus | potatoes, grapes, turnips, kohlarabi and mint | 1-Apr |
Rosemary | broccoli | carrots, potatoes, pumpkins and all herbs except sage | 1-Jun |
Rutabaga | peas, Squash, tomatoes, celery, cabbage, broccoli, Brussels sprouts, beans, onions, garlic, lettuce, Swiss chard, spinach, cauliflower, and radishes | brassicas (such as kale or cabbage). Root crops such as parsnips, carrots, potatoes, or beets | 1-Apr |
Sage | Rosemary. Plant Sage around strawberries, tomatoes, carrots, and cabbage. You might consider letting one or two of your sage plants flower. | Alliums: Onions, leeks, garlic, shallots, and chives | 1-Apr |
Spinach | Bush and Pole beans. Basil, chives, parsley, rosemary, sage, savory, thyme | Potatoes | 1-May |
Squash | radishes, corn, peas, beans, pumpkin, marigolds, and nasturtiums | Brassicas or potatoes | 1-Jun |
Sunflowers | plant sunflowers where you want to plant corn the next year. Chives to repel the aphids that attack sunflowers. Lettuce can benefit from the shade of sunflowers | Almost Everything. No joke. Sunflower seeds have what’s called an allelopathic chemical — one that inhibits the growth of plants in the area. | 7-May |
Tomato | basil, parsley, garlic, borage, squash, french marigolds, asparagus, chives, french marigolds and nasturtiums | Brassicas, such as broccoli and cabbage, Kohlrabi, potatoes and corn. | 15-Apr |
Tomatillo | peas, hot peppers and asparagus | fennel, dill, potatoes, egg plant, | 1-Apr |
Turnips | peas (best friends), squash, tomatoes, celery, cabbage, broccoli, Brussels sprouts, beans, onions, garlic, lettuce, Swiss chard, spinach, cauliflower, and radishes | parsnips, carrots, potatoes, beets or other root crops | 1-Apr |
Watermelon | peas, pole beans, bush beans, onions, leeks, chives, and garlic. Cabbage, broccoli, cauliflower, carrots, kale, okra, spinach, sunflowers, lettuce, and Brussels sprouts | cucumbers, summer squash, zucchini, winter squash | 15-Jun |
Oh no! I wish I’d read this before I started planning out my potted sunflower companions. Fortunately, one of them is a squash – so we’ll see what happens!
Do you know if some of these chemicals stick around if you clean and re-mix old potting soil?
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So, before I knew this, I would rotate out and plant new plants there the next year. They grew, poorly, and I always blamed the soil. We started making composting and mixing leaf matter and compost into the soil every winter and fall and everything grew much better.
The stuff I have read says the chemicals stay in the ground a while.
I would check out some organic gardening sites to see what they say. Last year I planted lettuce where I had planted sunflowers the year before. It grew… but not much. It got stuck at a small stage and didn’t seed in the fall.
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