Onions are a great neighbor in the garden, but if you combine them with the right plants, you can create a natural protective shield and stimulate their growth. This is the principle of combined cultivation, which uses the mutual exclusion of odors and substances.
Here are the best partners for your onions:
- Carrots: An inseparable pair (Pest trick)
This is the most classic and effective alliance in the vegetable garden.
Why it works: Onions repel carrot moths with their scent, which destroy carrots. Conversely, carrots confuse onion fly (a fly that lays eggs in onions) with their scent.
Result: Both crops remain healthy without chemical sprays.
- Tomatoes: Protector against diseases
Onions next to tomatoes benefit both parties.
Why it works: Onions secrete phytoncides that act against fungal diseases and molds, to which tomatoes are susceptible. Tomatoes, in turn, provide onions with a soft shade during the hottest summer days, which prevents the soil from drying out prematurely.
- Chamomile and Savory: Higher sugar content
Herbs are not just for tea in the garden, they are great “neighbors”.
Why it works: Chamomile planted near onions (a few bunches at the edge of the bed are enough) stimulates its growth and, according to old gardeners, improves its taste. Savory, in turn, helps in the fight against thrips.
- Lettuce and Cruciferous Vegetables (Cabbage, Broccoli)
Onions are an excellent companion for cruciferous vegetables.
Why it works: Onions repel leafhoppers and cabbage moths, which love cabbage and kale leaves. Since onions grow deeper and lettuce has shallow roots, they don’t compete for nutrients.
🚫 What to avoid with onions?
Some plants literally “suffocate” onions or inhibit their development:
Peas and Beans: This is the worst combination. Legumes fix nitrogen, which onions don’t need in the later stages, and they also secrete substances that stop the onion from growing.
Asparagus: Both plants fight for the same nutrients in the soil.
💡 Extra tip for a huge harvest:
If you want onions the size of your fist, don’t forget about wood ash. Onions love potassium. Just sprinkle it lightly on the bed before rain or watering during bulb formation (May/June).
Would you like to know how to make a natural spray from onion peels that will protect other plants in the garden?