If you use these bags for growing oyster mushroom (Pleurotus) types (e.g. on chopped straw), you need to punch additional, larger holes, e.g. approx. 7 mm diameter. Make the new holes when the bag is empty and still folded. Make them where the bag is two-layer (not along the folds). For still folded bags: Two rows of 6 holes (total of 24 holes per bag). Don't make the holes too near the bottom or near the top (after filling, the bags will be closed at the top). Extra holes are not required for growing shiitake. Note: the bags are not suitable for maturing your own spawn (requires special bags with bacteria filter).