We’re growing for medicine rather than making dime bags for weekend parties, but the THC cannabinoid that produces the so-called ‘psychoative’ effects is an important part of the medical effects – both symptomatic relief and the actual treatment. Because of this it’s a good idea to understand how this medicine is likely to affect you and how your harvest timing can influence this.

A fair number of people know the basic differences in effect between Sativa and Indica varieties – that somewhat buzzy effect of Sativa and the heavier couch-lock effect of Indica – but very few know that harvesting plants early or late can affect the, er, ‘effects’ even more than the underlying plant type.

If a plant is harvested early on in its flowering period, when the trichomes are visible (those are where the majority of the cannabinoids are found) but before they have fully matured, the resulting effect is more active and buzzy, the effects associated with Sativas. But if harvest is delayed so that the trichomes are starting to mature and get a little too old, a little oxidized, the baseline feeling it produces is much more physical. You may prefer a less physical effect, but be aware that early-harvest cannabis is a little more likely to cause edginess and even, in those prone to this, paranoia.

Patience is certainly a virtue when it comes to cannabis harvesting. Getting a cheap jeweller’s loupe magnifier can be helpful. So can a USB microscope, although be aware that a 50x magnification will be much more usable than a 500x one.

The trichomes are the small hairs that appear on and around the flower buds and nearby small leaves. When it’s around the right time to harvest, the tiny balls at the tips of these hairs will start to get a little cloudy. When it’s approaching the end of the normal harvest period, some of these will start to turn amber in color as they begin to oxidize. The plant’s potency will begin to drop at this point, so don’t leave it too long! If more than 50% have turned amber then you’re sliding past the ideal harvest point.

Don’t confuse the pistils of the cannabis flower for the trichomes; the pistils are the hairs that project from the buds from very early on, and these will change in color from white to orange or red as the bud ripens. This happens in advance of the trichomes maturing, so don’t be fooled by this and harvest too early.