They can discourage harmful pests without losing the beneficial insects.
I planted them around the corn, Broccoli, tomatoes, cabbage, & cucumbers, They seem to work for the corn & tomatoes the best. I saw no sign of the tomato horn worm this year in my garden.Last year they destroyed my corn.
I planted these every where. I fail to read the size of the diffrent types. The ones I planted by the tomatoes are as tall as the tomato plants.
The French Brocade Marigold has the added benefit of nematode suppression because its roots emit a substance that repels nematodes in the immediate area.
Grow is said to repel aphids, mites, and mosquitoes. Basil acts as a fungicide and can slow the growth of milkweed bugs.
I planted it with the Broccoli, cabbage & NASTURTIUMS.
Next year I will plant it by my Tomatoes It is said to (improve growth & flavor)
My garden protectors.
Reba & Crash
They keep out unwanted moles and critters. These 2 are something else. They chase and kill crickets, grass hoppers. Locust. And just about any thing that moves. My old cats in the city were not like this. They are true country cats.
I spread used coffee grounds in the garden to keep my cats from digging in the soil. Ground coffee is high in nitrogen so it is good for the plants also.
It is said that coffee has the ability to help suppress late blight. Also it can help reduce the ravages of slugs and snails.