Cabbages are killing my tomatoes – seriously?
Cabbages Are Killing My Tomatoes: Seriously?
I think my cabbages are killing my tomatoes. Last year my cauliflowers killed my tomatoes. But I am a sucker for punishment so this year I wanted to check it one more time. To see if the cabbages would do the same thing. Like a snake is still a snake and a lion is still a lion. So in the middle of July the verdict is in. The cabbage are winning this fight. They are killing my tomatoes.
Why are the cabbages stunting the tomatoes and making the leaves turn brown and discoloured? In my Companion Planting book it clearly says tomatoes and cabbage are good companions. But in Robert Kourik’s book “Understanding Roots” he disputes this companion idea.
Kourik quotes research about the allelopathic nature of Sunflowers, among other plants: “The inhibitory substances present in sunflower plants causing allelopathy could be used as a natural herbicide.” Used like a herbicide? Is this how plants kill other plants?
According to Kourik “… allelopathic plants include Brassica spp. (such as rapeseed, mustard, broccoli,[cabbage] and cauliflower), caster beans, chrysanthemums, marigolds and sesame.” So much for all the companion planting references that insist marigolds are good for your garden. The plant that is good for your garden is calendula (sometimes called pot marigold).
The massive roots in cabbage family plants means they take all available water and nutrients from a very large space (1.25 M x 1.25 M). The cabbage family is also one of the few vegetable families that does not co-operate with soil fungi so instead of embracing mychorryizae they kill them. Plants that rely on nutrient exchange from Fungi are at a loss in natural systems when the fungi are killed by the cabbage. So cabbage have an allelopathic effect, big greedy roots and an ability to kill root-feeding fungi. I will never, I repeat never, plant them in the tight quarters of my greenhouse with other fragile plants like tomatoes ever again. I promise.
Little Jobs in the Garden videos are posted on Facebook. Follow this link to the short video about cabbage
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