Let's get back to the subject here, which is about the issue of using cow manure for cannabis. The answer is YES. I personally use cow manure with EVERYTHING I grow, including cannabis. The mix is your preference, as some farmers prefer 1 part manure to 4 parts soil (1/4), or 1 part manure to 3 parts soil. I personally go with a 1-to-4 ratio because the native soil I have is already very rich, and when it comes to more "valuable" crops it is better to be safer than sorry. I have successfully used this recipe for several years consecutive with no negative results whatsoever. A popular recipe among veteran homegrown growers in the south is to use cow manure during vegetative state of cannabis, tomatoes, corn, etc, because it is very rich in Nitrogen and decomposes into extremely rich soil for future plantings! Cow manure is a win/win situation, and a great fertilizer thats even safe for beginner gardeners as there is minimal little risk of burning compared to much stronger and more dangerous fertilizers. Another great feature of cow manure is that it decomposes rather quickly throughout the long outdoor veg season, so you won't taste all those nasty nitrogens when it comes time to flowering. Other fertizlizers don't decompose as naturally, or quickly, meaning you will have to waste more time and energy flushing your plants of all those nasty chemicals. During the flowering stage, you can add potash and phosphate, but personally I've never needed to do this when it comes to cannabis. As long as your soil is quality, and you didn't go overboard on the compost/manure ratio, all you need to do is learn your watering schedule and your sativa's will be more than happy. I start early in the season (April), and my sativas average 12-15 feet in height and yield several pounds, using ONLY cow manure and native soil. I will start a journal this year of a crop I will grow strictly from mexican-brick bag seed, and show that anyone can grow quality buds and huge yield using a minimum of chemicals and tools.