Written by Mowgli Holmes, PhD
Today, most commercially available cannabis is grown from clones rather than seeds. Cloning is the process whereby a grower takes cuttings from a mature plant and roots them, allowing them to grow into new plants that are genetically identical to their “mother” plant. Most important agricultural crops are either grown from seeds or by cloning — but rarely by both methods. It’s yet another curiosity of the deeply unusual cannabis plant that it can be grown efficiently using either approach. But today cloning is king. Why?
The main reason is consistency. If you have a plant you like, you can take hundreds of cuttings from it, and if you treat them exactly the same, they’ll all be exactly the same. With the rising commercial pressures in the cannabis industry, this is a huge consideration. Not just because customers are starting to realize that they should be demanding consistency, but because growers need it even worse. If all your plants are the same, then all your growing conditions can be the same. It’s cheaper, and easier.
In the rest of the agricultural world, you can get this kind of consistency from a packet of seeds. If you buy tomato seeds, cucumber seeds, or pepper seeds, they’ll all grow into essentially the same exact plant. This is because modern commercial plant seeds are true-breeding, meaning they’re genetically stable, and give rise to basically identical progeny. Or they’re the result of a cross between two separate true-breeding lines, which results in near-identical progeny in the first generation. Either way, you can rely on seeds to be what they say they are, and to be the same.
Not so with cannabis. Some extraordinary things have been accomplished over fifty years of basement experimentation, but cannabis breeding is still effectively about eighty years behind modern plant breeding techniques. Very few cannabis breeders have created a true-breeding line. So when you buy a packet of seeds, they’ll all grow differently. They’re not a “strain.” They’re the diverse and unique children of two different parents; they’ll resemble each other about as much as humans resemble their siblings. Which is to say — only a little bit.
So here’s how most commercial cannabis growers use seeds.They order a bunch of them, probably from Holland. They plant as many as they have room for, squeezed together, and grow them to maturity. They examine all their traits carefully, and then they smoke them. They pick the ones they like, and put them in a “mother room” where the plants can provide a steady source of clones for the production rooms. They’ll give them a name — sometimes a brand new name (fair enough, because it’s a genetically new plant), and sometimes they call it whatever it said on the seed packet (which actually makes less sense, because it’s essentially giving a child the name of its parent or grandparent). Though perhaps we should just think of strain names as surnames; that’d actually be pretty accurate.
The whole process is often referred to as pheno-hunting, but it should actually be called genotype-hunting. And it’s good that people do it. It’s not breeding, but it’s been responsible for a remarkable flow of diversity into the cannabis market. The biggest reason for this approach is that once you pick a plant you like and start to clone it, all the clones are female. With seeds, you have to wait until you can identify the males, and get rid of them. Because males don’t make cannabinoids. But they do make pollen, which can fertilize all the female plants in a grow room, and cause them to produce harvest-destroying seeds. And who wants seeds?
But now for the drawbacks to growing clones. And they’re some pretty big drawbacks. Clones are easy to grow, and they’re usually healthy enough. But seed-grown cannabis plants have a degree of size, health, and vigor that clones can’t ever reach. This is partly because of the strong central taproot that emerges from seed-grown plants. Clones have a wavy scrim of roots, but no main taproot. And part of the difference is because clones have a tendency to “decay.” Cannabis growers all over the world describe this phenomenon: after a few generations, clones lose their vigor. They start to get weak, susceptible, lower-yielding…and then they often give up altogether. Beloved genetics often disappear forever this way. Many people believe this is due to “genetic drift”: some kind of progressive buildup of mutations, or perhaps a progressive wearing down of the ends of the chromosomes (a process that happens in many replicating cells, and is called telomere-shortening).
Mutations do, in fact, appear spontaneously as plants grow and could be passed on through cuttings. However, there’s no evidence that this leads to progressive weakening of clones over time. It seems more likely that something else is going on. Every now and then you meet growers who this doesn’t happen to — and they’re always the ones with the most obsessive cleanliness practices. Some of them run clones for years without problems. We think that “clonal decay” is the result of the progressive accumulation of plant diseases. This is partly because we know that the clone economy in states like California, Oregon, and Colorado has led to an historic spread of cannabis plant diseases. People have been sharing and selling clones for years, and the practice has massively expanded in the last decade. As clones travel between grow rooms, they carry disease with them — bacteria, viruses, fungi, and even insects. Growers know this, and paranoia is setting in. Many people won’t accept unknown clones under any circumstances now. But nonetheless the result of this clone economy has been a massive explosion of pesticide use.
I won’t get into pesticides right now. That’s a different story (read about the work we did on it here). But the point is that clones carry disease, and seeds don’t. (Although there is some evidence that seeds can still harbor certain plant viruses, we haven’t seen this for cannabis, and if it’s possible it’s certainly very rare).
Many growers, realizing the situation, are now turning to seed banks for the novelty that will fuel their businesses, rather than to trading in the trendiest new clones. And that brings us to the final problem with clones. The ones that catch the consumer imagination become incredibly popular. And even in the cannabis world — where some very non-traditional consumers are using the world’s most diverse plant — there’s still a kind of herd mentality. Last year, a huge percentage of flower sold in Washington State was “Blue Dream.” It probably wasn’t all really Blue Dream — this faddish mentality is one reason why we have the strain-name mess that we do now. People rename things to whatever is selling best. But nonetheless, what these trends lead to is monoculture. Monoculture is how traditional Big Ag does things. It’s not good for the environment, it’s not good for consumers, and it could spell death for the cannabis plant itself. If we don’t preserve the incredible diversity of this plant, we’re going to regret it forever.
Seeds are an incredible source of diversity, and the people using them are ensuring the future of cannabis. They also produce plants that are strong, healthy, incredibly high-yielding, and don’t spread diseases. On top of all this, it’s cheap and easy to grow from seed; cloning is a hassle. For all these reasons, we hope people will start to grow from seed more and more. We built our seedling sex determination test because we think they will — especially if it’s easy to get rid of the males right away.
We know that consistency matters. Until breeders start selling true-breeding seeds or consistent F1 hybrid seed, cloning will still be common in commercial operations. But it’s not so hard to create stable seeds, and it will happen soon.
The bottom line is that seeds are good. Cannabis growers are going to start planting them more and more. And they’re going to use them to grow tons and tons of really good pot.