In my grow room recently, I spent weeks dealing with tobacco mosaic virus (TMV) that would have killed my plants or ruined my harvest completely if I hadn’t worked hard to control the virus.
I managed to salvage my season and get at least some buds…about 60% of what I would have harvested if the plants hadn’t gotten infected with TMV, but at least not a total loss.
The good that came out of it is I learned how to care better for my plants, and to understand the full range of problems that can ruin a season.
Here are some tactics I used to keep my plants alive:
- As soon as I saw problems I changed out my hydroponics nutrients, root zone media, reverse osmosis water, and RO filters.
- I looked at my cannabis plants with a magnifying glass. I didn’t see any pests (pests such as aphids are known virus vectors), but I sprayed and root-drenched my plants with Azamax as a precaution.
- I gave the plants B vitamins, potassium silicate, and salicylic acid. They’re known to help plants resist stress, pests, and diseases. The products I used were B-52, Rhino Skin, and Bud Factor X.
- I sprayed and root-drenched my plants with Physan 20 three times, but stopped using it when I put the plants into bloom phase (because I didn’t want it to contaminate my buds). The Physan 20 manufacturer told me I could use it on consumable crops until about one week before harvest, but I chose to be cautious.
- I sprayed my hydroponics grow room and all its equipment (including fans and lights) with Physan 20. I also sprayed most of the rest of my house, especially areas in and around the gardening areas.
- I quarantined the worst-looking marijuana plants in a separate grow room after throwing away the ones that looked the worst.
- I spaced my marijuana plants more so that none of them were touching another plant.
- I mixed a fresh batch of nutrients every two days, and foliar-fed every other day.
- I gave the plants three weeks longer in grow phase to help them catch up to where they should have been. And because TMV slows growth and vigor, my marijuana plants took two weeks longer to finish in bloom phase than they should have taken.
- As soon as I harvested, I bagged all the root balls and stalks, all the pots the plants had been in, my Mylar, my remaining unused Pro-Mix, filters, and other grow equipment/infrastructure, and took it miles away and threw it in a dumpster. Then I sprayed the grow room areas with Physan 20 again. I sterilized everything I didn’t throw away.
- I got rid of the remaining seeds from the strains that had grown to have the virus. I’m pretty sure the virus came from clones, but viruses can travel in clones and in seeds, so I got rid of suspect seeds.
- Some strains were far more resistant and resilient. The Girl Scout Cookies and Blackberry Kush were the most affected. New York Sour Diesel and White Widow were the least affected by TMV.
I waited a month before I started another set of cannabis seeds, and only started five seeds to as a test to see if the virus was still present and active in my marijuana grow environment.
When the seedlings were six weeks old and showing no signs of TMV, I felt relieved that I apparently had a clean grow space.
As you have now seen from reading this four-part report (links to the previous articles are below), there are degrees of intensity and danger when you encounter marijuana plant problems.
Fixing marijuana problems caused by nutrients, water, grow room environment, and cultivation mistakes are relatively easy compared to dealing powdery mildew, spider mites, root aphids, fungus gnats, and gray mold.
And then there’s the worst marijuana plants’ enemy I’ve ever seen: tobacco mosaic virus.
If you’re lucky, you’ll never experience TMV in your marijuana grow op.
I lost a lot of money, rare clones, and time, and did many hours of extra work, just to rescue those infected marijuana plants, keep them alive, and get a way-smaller-than-usual harvest.
Read these previous articles for more important information about handling marijuana virus problems, and good luck!