Growing cannabis can be done in many different ways depending on your goal. Most styles of indoor cannabis cultivation incorporate a period of vegetative growth until a plant is big and strong before switching to the flowering phase. Growing cannabis this way uses about the same time frame as an outdoor grow and takes around 14 to 16 weeks. To take full advantages of the fact that you’re growing cannabis indoors however, it is possible to shorten this period significantly. By having a set of plants in veg and ready for flowering before you harvest, you can stagger your grow so that you can harvest every 60 days!
In this article we will discuss how to keep your (main) grow room in a constant flowering state. We do this by having a separate, but very simple, small and low cost vegetative room. Keep in mind that cycling your grows like this is best done with feminized cannabis seeds, because this setup does not really leave room for pulling out male marijuana plants. For the purpose of this article we work with 5 plants at a time because this is a common number of plants for home growers. This also means that 5 feminized cannabis seeds are planted every cycle.
Growing cannabis is best done with both a vegetative- and a flowering room. The purpose of the veg room is to fill the gap between seeds and the flowering plants. This will allow a grower to cycle his plants in such a way that the flowering room, which is really prime real-estate, never has to be used for vegetative growth. This is called crop rotation, or crop cycling. Starting from feminized seeds or clones is essential to keep your harvest cycles consistent. In this article we’ll describe how to apply crop rotation to growing cannabis indoors from seed, as we are of course proud to sell some of the best feminized marijuana seeds Amsterdam has to offer.
Vegetative growth is much less demanding than flowering, but does require 16-24 hours of light per day. It makes sense not to use a grow space and equipment designed for flowering full size plants to grow young seedlings.
We like to start preparing for a new crop around 30 days before harvest. This also means that the veg room is inactive for the first 20-55 of every flowering cycle, depending on the strain. 30 days is all your seeds need to turn into nice strong plants that are ready to enter the flowering room. To clarify, we’re talking about 30 days including the germination period.
Grow Pot Cheaply’s Youtube channel has a great video on how to turn a big cardboard box into a fully functional grow room. We wouldn’t advise using anything other than LED lights in this type of setup though, because the combination of cardboard and HID lighting is almost guaranteed to set your house on fire.
Once you know what type of light, plant and what pot size you’ll be using, it’s quite easy to figure out how tall your veg room needs to be. Add up your pots, plant height, distance to light and how much space the light takes up. Say we’re growing some Purple Berry Kush in 400mL, 10cm tall pots using a 50W LED light that’s about 10 cm thick. According to the manufacturer, the distance between the light and the plants needs to be about 25 cm. We’ll consider that Purple Berry Kush grows to a maximum height of around 25 cm when root bound in a 400mL pot.
So in this example we’ll need: 10cm (pot) + ~25cm (plants) + 25cm (distance to light) + 10cm (light) = 70cm.
Just to be sure, you’ll want some extra space so that you’re able to move the lights. Because we’re using LED or fluorescent lights however, it’s also not the end of the world if they get closer than 25 cm. We’ve seen people do it with less, but we recommend a veg room with a minimum height of 70cm. Make sure you adjust the distance to the light very often (daily) during early veg, as this will prevent stretching. Also keep in mind that the size of the pot determines the size at which your vegging plants become root bound. Smaller pots make your plants stay smaller and vice versa. After becoming root bound your plants will stay healthy for a few weeks, which means that less than perfect timing should not be a problem.
Towards the end of the vegetative phase, your plants will take up anywhere between 2 to 8 times as much surface area as the pots they’re in. Since we’re using square 400mL pots that are 10cm x 10cm at the top we’re growing a squat Kush variety, we’ll assume that we’ll be fine with a little over twice, so 15cm x 15cm, of surface area per plant. We’re using 5 pots, so a length of 3x15cm = 45cm and a width of 2x15cm = 30cm, or surface area of 45cm x 30cm = 0,135m² should be enough. Having extra space is better of course, but that goes against the whole idea behind this article.
Environment-wise, vegetative growth is at its best around 24 degrees celsius with ~80% humidity to replicate the spring in a natural outdoor calendar.
Your freshly planted feminized cannabis seeds won’t need H.I.D. lighting just yet and will do fine with a less powerful light. Until they have germinated they won’t need any light at all. The first couple of days after germination won’t require anything more than a small fluorescent light. Even cheap CFLs can provide enough light for the first few days. For a 30 day vegetative phase we recommend about 50-100 watts worth of CFL or a LED light that draws around 50 watts.
The very best method is to have fully equipped veg and flowering rooms with strong lighting, but this is not really necessary. You don’t really have to aim that high, if you’re looking for minimal power consumption and a low cost to set up, a simple bedroom cupboard with a few CFLs will do fine.
Even if you get a good deal, feminized cannabis seeds can be expensive and deserve to be handled with care. We recommend following our germination guide for a maximum success rate, but you can also skip a few steps and plant directly into a starter plug or even in the medium.
We recommend starting your feminized cannabis seeds in smaller pots and then transplanting them into larger pots when moving to flowering room. This allows your veg room to be much smaller than your flowering room. It also lets you to plant more than you need so that you can select the best ones for flowering.
Starting in a small pot also gives cannabis plants the chance to really fill out their root system. As we’ve discussed earlier in our article about air pruning, this will improve their growth when transplanted. And since more roots equals more fruits, they will have a head start once they hit the flowering phase. It is also a good idea to try and get pots that will air prune your plants to further increase the density of the root mass.
We recommend using a 400mL-1L container for vegetative growth. Popular options include 400mL square pots and 500mL plastic cups, but 1L fabric pots are probably best. After finishing the vegetative phase, you should transplant into 10L+ pots for the flowering phase.
This style of growing works for both soil and hydro and is not very different between the two. If you decide to take the hydro route, it is likely that you can plant your feminized cannabis seeds a bit later. Growing cannabis hydroponically does not speed up the flowering phase, but can be up to 20% faster than growing in soil during the vegetative phase.
Your 5 feminized plants in the veg room are now 30 days old: they are ready for transplanting and flowering. We use our Moon Walker Kush as an example in this text, as it takes 60 days of flowering to be ready for harvest.
After rotating your 30 day old, freshly transplanted female cannabis plants into the flowering room, you will wait for another 30 days to pass. After these 30 days you’re at the halfway point of flowering and should start the next set of feminized cannabis seeds. In another 30 days the first set of cannabis plants will be done flowering. You will then be ready to replace your harvested plants with the 5 new cannabis plants you have growing in the veg room. Your rotation is now in full effect!
The flowering room needs to be around 22 degrees celsius with less than 50% humidity, the less humidity the better. If there is too much water in the air this can cause problems with plant respiration and can lead to fungus and mould. Large budding plants can get in trouble quickly if the humidity is too high and the amount of air movement is too low. You should be especially cautious during the night as this is when humidity tends to rise significantly. For the best results, keep the humidity level around 30% and ensure there is enough air circulation.
Your yields are largely determined by how well your plants do during flowering, so you want a powerful light for this phase. In the flowering room, you will want to use a HPS or LED. These should be high powered, we recommend a minimum of 400W for HID grow lights a decent return on the gram per watt scale. The exact numbers for growing cannabis with LED lights are a bit unclear, but manufacturers often compare their lights to HID lights. Again, go with a LED light that matches at least a 400W HID light.
Remember that you want to provide your entire canopy with enough light. You may even want to use multiple lights to get the most production possible from your cannabis plants. Two less powerful lights often provide better coverage than a single powerful light.
Your flowering room is responsible for turning over a few hundred grams every 60 days so the focus here should be on maximum lighting and maximum production! Make sure you read our article on how to yield more from the same grow lights for further information on this subject.
After 60 days of flowering, your cannabis plants should be ready for harvest. Chop down your plants and trim away all of the twigs and leaves. After this you can hang entire branches or put everything in a hanging drying net.
Many growers have a specific drying room or tent for this purpose to avoid having to dry their buds in the flowering room. A drying room should have <50% humidity, be around 20 degrees celsius and have a very soft breeze to circulate the air. The room should also be dark, or at least not be lit by direct sunlight. Never have a fan blowing directly on buds as this will dry the buds too fast and make for a harsh smoke.
If you are able to control the humidity and airflow in your veg room very well, it is possible to dry your buds in the veg room. This way you can avoid dedicating yet another space to growing cannabis, as your veg room will not be used for another 30 days anyway.
It typically takes 10-14 days for the buds to fully dry. You can tell they’re ready when there is an audible snap when breaking the buds. Drying is considered the last and most important step when growing cannabis as this will make or break your harvest. Your bud is ready to be smoked after drying, but will be much better if you cure it for at least two weeks.
While some parts of this article may seem a bit obvious, we hope to have given you some good advice on growing cannabis more efficiently. By introducing crop rotation in the way we describe, you save time, space and money. This way you get maximum return for minimal effort. With or without rotation though, growing with quality feminized cannabis seeds is never a bad idea!