Ask Erik - Mold on Cuttings
Erik,
I start my cuttings in trays using small rockwool propagation cubes. I have noticed that a white-looking mold has started to grow on the surface of the cubes and it is starting to grow on the base of the stems of my rooted cuttings. I am worried this will harm my plants. Is there anything I can do to get rid of it?
Molds may occur more readily during propagation if the rooting medium remains too wet, especially if spores are present in your growing environment or on the donor material used to propagate cuttings.
A foliar application of a product containing silicate on the surface of the growing medium and base of the plant will help to rid you of the mold and strengthen the cells of the plant. Plants treated with available silicate will be more resistant to many diseases, insects, temperatures, and drought. Silicate provides a barricade around plant cell walls, and the thickened cells allow the plant more resistant to stresses. Silicate-based products applied to the surfaces of the growing medium and plant will also alter the pH on those surfaces, making them inhospitable to most molds. Applications of silicate may also reduce the incidence and effects of stem rot and other plant diseases.
Although it is important to keep the growing medium moist for non-rooted cuttings, do allow the cubes to dry enough so that they don’t remain saturated for periods of time. If you are using humidity domes, lift them off for a few minutes a day to let things breathe. You can also wipe away any condensation on the lids with a clean paper towel. Under most conditions the cuttings should have rooted before they require additional irrigations from the initial pre-soak/treatment of your rockwool propagation cubes.
Once plants are rooted, make sure there is adequate spacing between cubes so that air can circulate around the growing medium and plants, and allow the top surface to dry out slightly between waterings.
Cheers,
Erik Biksa