Ending Powdery Mildew

Treating Powdery Mildew

Beware the cursed powdery mildew, a mold that grows on your leaves and buds. It looks like somebody sprinkled little roundish spots of talcum powder on your leaves. It saps the strength and vigor of your plants, and, when smoked, may pose a health hazard to those with compromised immune systems.

There are a few ways to fight the dreaded PM. Regular sprayings with neem oil during veg and early flowering is successfully employed by some growers. Some use Serenade, an organic bio-fungal, and there are a few other products available at the grow store that work to varying degrees. An organic “systemic” called Aqua-Shield is available from Botanicare. It is made from composted “poultry litter”. (I’m glad I’m not the guy with the job of brewing that stuff up).

 The best method, of course, is to not get the stuff to begin with. Keep the humidity way down and provide the plants with a lot of internal air circulation.

Another way to not get PM, and to successfully get rid of it if you do get it, is to evaporate sulfur. Sulfur is a naturally occurring element that has been around since forever, and the human body is used to it. As the sulfur can be used in its natural state, treatment with evaporated sulfur is within the bounds of organic gardening techniques.

In essence, a device heats up the sulfur until it melts at about 360 degrees Fahrenheit, and the sulfur fumes coat everything in the room or greenhouse. This raises the pH of the leaves and flowers to about 11, and no mold can grow at that level of pH. Greenhouses have used sulfur evaporation to prevent and treat molds and fungi for decades.

The same techniques work just as well in an indoor gro room. Sulfur evaporators are available at the grow store. They look like a paint can with a bail handle, and electric cord, and a tuna fish can on top. The operation is pretty simple. The heating element raises the temperature of the sulfur until it melts, and the fumes fill the room and coat the plants.

Beware the sulfur evaporators that come from the grow store. They cost over $100. and have a nasty habit of bursting into flame, burning up all the sulfur in a few minutes, and filling the room with enough fumes to kill all the plants immediately. (In all fairness to the sulfur evaporator manufacturers, they have changed their operating instructions to lessen the possibility of a fire by raising the sulfur cup up off the burner by an inch. I thank them for this, but I wish they would have made the change before I bought the damn thing.)

Instead of spending a hundred  on one of these, a frugal grower can go to Wal-Mart and buy a Rival electric skillet for $19.95. Buy your sulfur at the grow store. Turn off all the fans, turn off the grow lights, fill the fry pan about a half inch with sulfur, set the temperature to 400 degrees, and melt the sulfur. Turn the fry pan off after the fumes fill the room. Don’t breathe the sulfur fumes.

Sulfur fumigation does impart a sulfur taste to the produce if done too close to harvest. However, a tiny bit of sulfur in the aroma is far better than a crop ruined by PM. Light sulfuring done on a weekly basis will prevent PM from spreading or reoccurring. Heavier sulfuring every four or five days will eliminate a substantial infestation after a few weeks.

Sulfuring also treats, prevents, and eliminates bud rot. It controls thrips by interrupting their reproductive cycle, and spider mites would rather set up housekeeping somewhere other than in a sulfured grow room. Just be careful not to overdo it. Too much sulfur results in burned pistils in the buds closest to the evaporator, but the growth of the bud does not seemed to be compromised very much, if at all. Way too much sulfur turns the leaves yellow in the margins between the veins.

There is a controversy as to whether one should run a circulating fan while sulfuring. I run an oscillating fan at slow speed in the grow room for about half of the time I am sulfuring.

SIDE-BY-SIDE GROW TESTS – YOU CAN PARTICIPATE AND HELP ADVANCE OUR SCIENCE

Our grow class has worked on and developed several new technologies, one of which is the Solaround light mover, a remarkable new twist on light movers which shows tremendous promise. (Check out the “resin-stressed” Hindu Skunk on the menu board!). We are about to conduct two new experiments, and members of DharmaRx who are patient / cultivators can participate. In a nutshell, we are going to do several side-by-side growing experiments, testing the claims of a nutrient manufacturer in one case and the claims of many outdoor growers in another.

Since planting time outdoors is rapidly dwindling as this is written, let’s start with an outdoor experiment. Foxfarm vs. Miracle Grow One of the first things covered in D. Gold’s grow class is the importance of good potting soil. There is a reason that Foxfarm at the grow store costs several times as much as Miracle Grow at Home Depot. The concept of spending another five bucks on potting soil to reap another $100 or more worth of medicine is a pretty sound one.

Miracle Grow potting soil has traditionally contained lots of dirt and very few amendments or nutrients. It has often been said that it would be a miracle if you could grow good cannabis in Miracle Gro. But the company may have recently seen the light. They now have two new potting soil blends that growers are trying with results good enough to talk about. The one side-by-side outdoors test that I recently witnessed produced results that are about equal to Foxfarm, and quite a few other growers have been singing the praises of the product, saying that it gets great yields and quality with a whole lot less work.

Testing potting soil in a controlled experiment is pretty easy. Simply plant the same plants in the two different types of soil and keep all the other conditions the same. One need not be Einstein to be able to observe the differences. In this experiment, we are observing Foxfarm Ocean Forest, Miracle Grow Organic Time Release, and Miracle Grow Time Release (non-organic). If you have a mix you like, add that one also. Water all the plants with the same fertilizer mixture (or lack thereof) and make sure that all the plants grow in identical conditions.

Keep good records of your fertilizer mixtures. Remember that in cases like this, it is probably better to keep the levels of added nutrients relatively light, in order to avoid overfertilization.

The second experiment pits General Hydroponics against Advanced Nutrients. Many members of the class have been bothered by a film on U-tube which claims over 20% THC with Advanced and only about 6% with GH in a side-by-side controlled test. Many believe that THC levels have more to do with genetics than a feeding program and this wide disparity could not have occurred in a true, non-biased, controlled experiment. We will set up a detailed side-by-side experiment that all the patient / cultivator members of dharmaRx.org can participate in, if they so wish. If you are thinking of giving hydro a try, here’s a good opportunity as a detailed method for inexpensive set-up and efficient production will be presented in great detail. Stay tuned!

Organics vs. Hydroponics

Let’s begin with a subject that always comes up in my grow classes: the difference between organics and hydroponics. Here’s my take on it; feel free to add your two cents worth, or call me on mine. I look forward to hearing from you!

While there are several forms of hydro, the general idea is that the roots of the plant hang in a solution of nutrients which supply the plant with all its fertilizer needs. The nutrients are derived from minerals which are usually mined in the desert. Organic growing, as it pertains to modern cannabis production, usually starts with a potting soil containing nutrients derived from animal feces. The plant must go through more metabolic processes to obtain what it needs from the organic nutrients mixed with the soil than it needs to in order to absorb nutrients from a hydroponic solution.

Organic soil growing is kind of like when a human eats a piece of bread. The stomach slowly converts the starch to sugar, which slowly goes out into the body and provides nourishment. Hydroponic growing, on the other hand, is like an intravenous drip of sucrose right into the bloodstream.

As a general rule, organically-grown medicinal cannabis tastes and smells better than hydro and also smokes smoother. For this reason, top-quality organic medicine commands a premium over hydro-grown. Organic hydroponics can be done, but is a more difficult proposition than utilizing mineral nutrients. Botanicare has a chart which shows how to replace the traditional General Hydroponics three-part formula with organics, a little at a time. These formulae can be used to add some organics to the traditional hydro mineral mixes, resulting in an enhanced taste and smell, or can be used to make the shift to 100% organic hydro. I have never actually undergone the GH to Botanicare / mineral to organic hydro conversion, but it seems like a pretty straightforward transition.