No, mold is simply one of the tools mother nature uses to decompose organic substrates.  Mold growing inside a confined space, where we breath in the concentrated spores, is very potentially harmful.  Absolutely mold growing in your home is not healthy.  Plants growing in a bale with mold on it are completely unaffected and actually benefit from the mold as mold is a decomposer, helping to break down the substrate into soil.  Plants don’t breathe in and out like we do, so the mold doesn’t affect them at all.  Mold growing on a bale will usually be attacked and consumed by the bacteria present in the bale shortly after it gets established.  If a gardener has serious allergies to mold, then I would recommend wearing gloves, and a mask when gardening period, with bales or regular soil.  If allergies are bad enough then maybe gardening in general just isn’t for you, stay indoors where your less likely to suffer any encounters with mold spores.   Soil generally contains lots of mold spores as well, as does most air outdoors in the summer.  The concentration is much lower than indoor air can be in a moldy house however and the lower concentration of spores is typically never a concern fGorgonzolaCheeseor most people.  I would not recommend eating vegetable leaves with mold on them, for instance if a lettuce leaf came into contact and was smeared with mold prior to harvesting it, then I would suggest washing it well before consuming it.   We eat moldy cheese all the time, they even charge extra for the moldiest of cheeses.  Most mold itself is pretty harmless, but less than tasty to eat.   Think about your straw bales like cheese, the moldier the better.  Stop worrying about what you assume is going to go so terribly wrong with your Straw Bale Garden, and just get started.  You’ll see that most of these concerns you have about moldy bales are completely unwarranted in the end.


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  1. It seems to me, planting potatoes in a moldy bale would cause the potatoes to be moldy as well. Is this not the case?

  2. Corinne Nygren

    This is ny second year of straw bale gardening. This year my bales have a lot of fungus and mold on them and so do many of my plants, honeydew, muskmelon, zucchini and some tomatoes. I didn’t have that problem last year. Is it possible the mold and fungus from the bales is transferring to the plants?

    I live in Wyoming, MN – we’ve had a dry summer so I’m not understanding why we have more mold and fungus this year than last year when it was so wet.

    BTW, We attended your session at the MN state fair, bought your book and started straw bale gardening and are very happy with this method. I love the no deweeding!!!!

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