2020 Isolation Grow: Sexing

May 4, 20202020 Isolation Grow Blog

This will be my third year of growing exclusively with seeds, so it will be my third year of sexing. I have had two completely different experiences so far, which is not unusual. The first year, I had more females than males, which is unusual. I started very few seeds and got lucky.

Last year, on the other hand, was the year the boys more than evened the score. I expected more males, and started more seeds to hopefully compensate. I started 70 seeds, and 63 turned male. I only had seven regular female seeds. I filled in my beds with feminized seeds.

This is entirely luck of the draw. You don’t know what you have when you start. You hope to be lucky, and some years you are. Last year was brutal.

You can start sexing at 3 weeks, and there are usually several that show between days 21-28. The last two years, I have given the youngsters their first sip of compost tea on week four. It might be coincidence, but each year, that tea seems to have caused most of the males to show themselves within 48 hours of the pour. I don’t know if that little boost of complex sugar and light nitrogen from worm castings is the reason the boys showed themselves, but it certainly does seem to impact most of the males in the room. Two days after they got their first sip last year, 27 plants turned male one day. I called it the Sunday Slaughter. Every hour, I would walk out to the cottage and inspect, only to find more had just turned. They show their pollinating sacks very quickly, and there is no denying them once spotted.

So last year, in addition to starting our feminized seeds later, to fill in the beds, I had to start more regular seeds after sexing. I started 20 more, and still only got two more females. Thankfully, this was enough to fill in our beds. However, several cultivars were not moved to the beds until between June 15 and June 23. Those plants grew and flowered, but were not as potent as plants put in the ground three weeks earlier.

I had young plants in the beds, and I was still trying to coax more females out of seeds in the cottage. It turned out to be a very good crop, but I am constantly reminded that it could have been better.

The art of sexing plants is relatively simple at first, but more complicated if they don’t show early, or if the seeds are feminized, and those plants become stressed. But generally, many plants can be sexed relatively easily. Sex is shown in the nodes where leaves and branches extend from the stalk. If you are lucky, by week four, you’ll be able to see the signs of pre-flower, though some seeds take longer to show than others. Some cultivars do not fully show their sex until nearly six weeks. It is wise to not put a plant in a bed until sex iis determined. I’ve had two plants turn male in beds, because I planted them prior to six weeks on nothing more than wishful thinking. Those beds ended up empty for that growing season, which is a waste of a good growing medium.

Male flowers form as two hairless sacks. Females form little tear shaped bracts in the same spots as males, but they have hairs extending from the tops. When you see those hairs, you know you have a female. I’ve had females show themselves as early as four weeks, and others have not shown until planting day, at six weeks. Sexing is the first time I break out the magnifying glasses for the grow. I’ve become good at spotting male pollen sacks with the naked eye, but I always confirm by looking through a mag lens. These pollen sacks are very small. After sexing, we put the mag glasses away until plants are close to harvest.

I like to wait a couple of weeks before starting the feminized seeds. They do not need to be sexed. As previously mentioned, I’ve had better luck planting feminized plants after four weeks, than six. I have had feminized plants attempt to flower early and I’ve reversed them using the method described in the Compost Tea blog.

However, I am mindful of feminized plants. I try everything in my power to not stress them. Stressed feminized plants can go hermaphrodite and produce both male and female sex organs, and can, alas, pollinate the entire garden.This would not be good for any cannabis plant I have growing, or frankly, any cannabis plant growing nearby. That’s why you have to wrap and remove males or hermies IMMEDIATELY. They can pollinate other cannabis growing in the neighborhood. It is irresponsible for a grower to let a male plant flower outside. All outdoor growers have the right to seedless harvests.

Things that can cause hermaphroditism can be both genetic and environmental in nature. Some cultivars are simply more prone, but in my experience, the greatest cause is stress, and that can be varied. Stress can include too much heat, broken branches from accidents, irrigation issues, over-fertilization, insects, pathogens, pesticides, even using water that is too cold. Another factor is that cannabis is hardwired to reproduce, so it feels unnatural for there only to be female plants in the cannabis garden. My observation is that many of these factors are mitigated by a consistent approach to the care for the plant. I water the same day and the same amount. I try to prune in even cuts around the plant. If I see a plant needs more pruning, I might designate which branches are going to be cut by wrapping colored tape close to where the branch will be cut, and wait a few days.

I have had one plant go hermaphrodite on me, and that was the year we opted to not use BT. One of our cultivars was CBD Therapy, which came from feminized seeds. I cannot be 100% certain, but in my heart, I know my decision to not spray brought stress to that plant. We grew three other seeds from that cultivar, and they were fine.

I use feminized seeds now to fill in the gaps of my crop. If I’m lacking CBD, I’ll grow more AC/DC. If I’m suddenly a little short on THC, I’ll grow a White Widow or a Rainbow Kush. I’ve also noticed that feminized seeds tend to be growers. Last year, the four feminized plants we grew netted 9.2 pounds, well over half our total yield. In this way, I attempt to maximize our annual yield by making certain all our beds are full.

The bottom line on feminized plants is to consciously limit the amount of stress they recieve, specifically during the flowering portion of the grow. Training should be completed for feminized plants prior to flowering. Once the flowering process has begun, there should be as little done to disturb her as possible, other than pruning smaller branches away from larger flowers. The feminized plants I have produced have been consistently high in yield.

It is a happy day for me when sexing is complete. Sexing is stressful, because my entire crop depends on developing enough female plants.

Sexing begins at three weeks and ends at six weeks. But once you can determine the sex of a plant, you are close to putting them in the final growing medium.

There is only one time I’m happy to see a male cannabis plant, and that is over the winter, when I’m producing seeds. Not right now.

Jeffery Hickey
Oaksterdam Alumni

Jeffrey Hickey is a 2014 IPPY award winning novelist, performing in over 900 Reader’s Theater shows that featured his authorship of adult novels, and books for children. His accomplishments include a program of self-empowerment and effective oral communication, “Find Your Voice,” that he taught in public and private schools throughout Northern California. Jeffrey is the father of twin sons, and is arguably the happiest married man on the planet.