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splatteredwhim

Roots growing too much in containers?

splatteredwhim
11 years ago

Hello,

I grow herbs outdoors on my balcony in containers (this is my only space) and I think the roots are growing disproportionately fast. I repotted everything (sage, rosemary, mint, oregano, thyme, lavender, and catnip) back in mid-to-late-April, and most things have giant masses of roots coming out the bottom already, and leafy growth has slowed, and some things are starting to yellow.

Should I really have to be repotting into bigger and bigger pots every month or two? I can understand this for the things in the smaller 12 inch pots, but some are in 24 inch ones. Or am I doing something that encourages root growth instead of leaf growth?

Comments (4)

  • Daisyduckworth
    11 years ago

    You aren't doing anything wrong, and the plants are doing what Nature intended. One thing that astonishes beginners more than anything else is the sheer size of most herbs when mature. We are used to seeing tiny seedlings in tiny pots and our minds have trained themselves that this is what a grown-up herb looks like. HUMPH to that! Think of a plant that, in diameter, is much too big for a person to hug.

    Those roots are searching for more space to spread. If they can't find it inside the pot, where else can they go but outside it? If they locate a patch of dirt, they'll propagate themselves by self-layering.

    You can cut off those roots outside the pots without doing the plant much harm - but sooner or later you'll need to transplant to much larger pots, especially the mint which can spread like wildfire.

  • eibren
    11 years ago

    Daisy, are the roots of these plants useful for anything?

    I feel they could at least be left out as nesting material for birds....

  • splatteredwhim
    Original Author
    11 years ago

    Ok, thanks. It just seems like they are going so fast down below! Could I prune the roots and keep them in the same pots for a season, without doing terrible harm? Or is that a bad idea?

  • tapla (mid-Michigan, USDA z5b-6a)
    11 years ago

    Proper root pruning actually has a rejuvenating effect on the plant. In container culture, the large roots are essentially worthless, except as plumbing to handle the flow of water/nutrients and photosynthate/bio-compounds, and smaller roots serve just as well to that end.

    I regularly root prune all my woody plants severely - including my herb grown as bonsai. The procedure for your plants would be the same. I don't happen to have any pictures of herbs I've root pruned, but here's a little boxwood to illustrate how much root pruning a woody plant will tolerate if you know what you're doing. If you don't, I can help you learn. I'll leave a link that should be helpful after the pictures of the little box.

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    Al

    The link below is focused on trees, but repotting your herbs vs potting up has the same value for herbs as for other woody material. Potting up when a plant becomes root bound ensures limitations - that a plant can never have an opportunity to grow to it's genetic potential (within the limits of other potentially limiting factors), while repotting (which includes root pruning) ensures at LEAST the possibility. Be aware that when repotting, timing is important.

    Here is a link that might be useful: More about repotting/root pruning .....

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