Companion planting is somewhere between a science and an art, and we certainly haven’t figured it all out yet. Certain plants can benefit each other by trading valuable nutrients through their roots, or masking smells which confuses pests. They can also provide shade where needed or form a living mulch. Certain plants can attract beneficial pollinators or insect predators. There are even plants that will mine valuable nutrients up from the depths of the soil or even fertilize the soil with their root nodules.
It has been said that plants that go well together when cooking, make good companions in the garden as well. For example, basil and tomatoes make good garden companions. Carrots and tomatoes are famous companions. In fact an entire book was written on the subject entitled “Carrots Love Tomatoes”. Onions make great companions for carrots as the strong onion smell helps to repel the dreaded carrot fly. I would imagine any plant in the allium family could serve this function such as garlic, leeks, shallots, or chives.
The three sister’s garden is a very famous trio to plant together. The corn provides a sturdy trellis for your pole beans, while the pole beans provide the valuable nitrogen fixation that the greedy corn desires. Your squash provides a wonderful groundcover that suppresses weeds and confuses pests, while the corn provides the shade that a woodland plant like squash craves. You can also do variations of this theme. You could substitute sunflowers for the corn, or cucumbers or watermelon for the squash. I have to find a good substitute for the reliable hardworking pole bean though.
The combinations and possibilities are endless. I do companion plant my zone 1 garden, but I also follow a yearly crop rotation schedule so pest and disease pressures as well as soil deficiencies don’t develop over time. I break my garden up into 12 different plots that are rotated each year. I try to follow the crop rotation schedule as well, although when I am mixing so many plants together, it is hard to follow it perfectly. Most importantly, I will plant a lot of legumes the year before my greedy plants go in, as the legumes will deposit the nitrogen into the soil that the greedy plants need.
Below is a list of my crop rotation schedule and the plants that I grow together as companions.
Crop rotation schedule
Legumes (Beans &Peas)
Greedys (Tomatoes, Peppers, Corn, Squash, Cucs, Watermelon etc…)
Salad and Root Veggies (Lettuce, Carrots, Beets, Spinach, Turnips etc…)
Plot 1 Brass, Potatoes & Swt, Onions, Mint (In pots), leeks
Plot 2 Brass, Potatoes & Swt, Onions, Mint (In pots), leeks
Plot 3 Beans, arugula, Eggplant, Lettuce, spinach
Plot 4 Watermelon, Corn, Radish, Beans
Plot 5 Eggplant, Beans, Peppers, Marigolds, Mint (Pots)
Plot 6 Squash, Corn, Beans, Radish Watermelon
(Keep Beans away from marigolds)
Plot 7 Lettuce, Radish, Beans, Carrots, Mints (Pots), Parsnips
Plot 8 Cucs, Radish, Marigolds, Peas, zucchini, lettuce
(Keep Peas away from marigolds)
Plot 9 Spinach, Peas, Beans
Plot 10 Corn, cucs, beans, squash, soy, sunflowers
11- Peppers, Tomatoes, Geraniums, Basil, Oregano (Pots)
12- Tomatoes, Carrots, Mint in pots, Basil, Oregano in pots, Onions, Marigolds