Growers of autoflowering varieties will get best results when they plant the seed directly into the final pot, and need to pay very close attention to seedlings for the first three weeks. Mistakes in the vegetation period of autoflowering strains have fatal consequences, meaning low yields. Depending on the strain and growing method, pot sizes ranging from 5-15 liter can be used. The size of the pot will have an influence on the size of your plants, on yields, and on the frequency you water your plants. Tip: Airpots allow more oxygen to get to the root system and will boost vitality and final yields.
There are basically two different techniques that are commonly used to germinate cannabis seeds.
After seeds have germinated, it’s time to plant them into the pots. Plant the seeds just 3-5 millimeters below the surface of the earth, ideally with the tiny root facing downwards. This can help to avoid time-loss and seeds don’t have to figure out how gravity works.
Aim for humidity levels of approximately 70%. Small propagators can be an option if you start in very small containers but autoflowering growers planting in final pots need to monitor, and eventually raise, the humidity inside the grow room.
Mastering the delicate seedling stage is crucial to grow strong and healthy cannabis plants. Read this blog for further information on how to cultivate cannabis from seed to seedling.
High quality organic soil that is “light” when it comes to pre-added nutrition works best.
Before germinating our cannabis seeds, we make up our mind about containers and soil, assuming most rookies prefer soil due to simplicity. At this point, we already need to differentiate between autoflowering – and feminized/regular seeds.
It’s not necessary to use your powerful HPS or LED the first 10-14 days. CFL’s with a blue light spectrum (daylight/coolwhite) will get you very good results. Either built your own light fixture using T5/T8 sockets or buy 23-30W CFL’s with the standard European E27 lamp socket. Compare different bulbs and choose the ones with highest lumen output.
Simply drop your seeds into a glass of drinking water and wait 24-48 hours until seeds have cracked. Wait until you see the first few millimeters of the root, and make sure water temperatures are between 20-25 °C. Place your cup somewhere light doesn’t reach it.
Are you concerned about the delicate seedling stage when growing cannabis? Don’t be! Follow these 3 steps and cultivate healthy seedlings.
Luckily, there is no major harm done if the situation is dealt with quickly. Some people opt to stick a support stake (a straw, pencil, chopstick) until the plant grows out enough to support itself. This works, but is not the optimal solution.
Seeds are like little genetic time-capsule bombs. What this means is that they only have one job, and only get one chance to pull it off. They are pre-programmed to survive. A seed self-contains absolutely everything a future plant needs to get started. Once activated with moisture and darkness, it will trigger germination, and once that gets going, there is no turning back.
This may seem a bit confusing for new indoor growers, as they may think they are providing more than enough light to their plants. But consider the following. Positioning a 200W metal halide bulb very far away from the pot will be less effective than a 20W CFL bulb a few inches away from the leaf surface.
Seedlings are programmed to survive, so if they are stretching, they are stressing. Learn how to fix this occurrence and prevent it from happening in the future.
In optimal conditions, the seed shell, or husk, will crack open and a taproot will pop out, immediately digging further down in search of a water lifeline. Soon, you will see a sprout rise from the under the soil, spread out its first baby leaves (cotyledons), and then you will start noticing the first set of true leaves. Leaves have an equally important job as the taproot, but they are in search of another food source – light. Quite literally, a plant uses light to digest what it brings up from the soil.
In the same way a taproot digs for water and nutrients, the top part of the plant will stretch vigorously if it is not receiving enough light. It is a survival mechanism. It will use up all its stored energy to rise above competing flora. In the case of indoor growing, there is no competition, but the seedling will perceive it this way. For instance, leaving the pot under a windowsill in the shade will likely trigger this behaviour.
Just like baby newborns, seedlings are very delicate things. They need as much tender loving care as possible. And in the case of our beloved cannabis plant, the best form of TLC is to provide it with ideal environmental conditions.
Seedlings have very little leaves. The total surface area in which to absorb light is very small. So, in essence, that 200W bulb will be radiating over a very large area, but the seedling can only use a minute fraction of it. The CFL position right over the plant will be able to give most of its 20W directly.
Give your babies direct sunlight, not shade. If growing indoors, lower your lights if possible. Just be sure that potential heat stress is not a problem. HID lights may be too heat-strong for seedlings if you set them too close. Lower-powered LED or CFL may be a better option at this stage.
What causes exacerbated stem growth of seedlings, and how is prevented? Find out here!