Expansive healthy roots mean strong turgid plants and fat resin jewelled buds on your mature marijuana plants. Type big into a thesaurus. All those words are what you want for your cannabis plants in every way. You have already decided what grow method you are going to use to make the most of your space. Indoor or outdoor. You will have space for a larger number of small pots as in SOGing or a smaller number of large pots as for ScrOGing or a standard tipped and mainlined grow. You may even be going for broke and have one large pot for a single large space filling marijuana plant. No matter what, you will be transplanting into bigger pots at least twice.

Terms

Pot on: transplanting to a larger pot from a smaller pot.

Re-potting (root trimming): transplanting the plant back into a pot of the same size with a fresh growing medium.

Here we only discuss the appropriate double entendre, potting on.

WHY POT ON?

Knowing how and when to transplant your babies can add days of resin production in the final weeks of maturation. Little to no transplant shock means minimal time wasted by your plants recovering from broken roots, collapsed root balls or pot binding. Unlike hydroponics or deep water culture, growing in a solid medium like soil or coco makes potting on necessary as your plants grow. The goal is for the roots to keep seeking out from the stem and delay coiling in the pot for as long as possible. When roots start to fill the volume of the pot too much, vegetative growth will slow.

HOW DOES POT SIZE AFFECT CANNABIS GROWTH ?

In nature, the spacing of plants affects their habit. When cannabis is planted for industrial purposes it is planted very close together. The resulting root tangling releases hormones that encourage a tall plant with no true side branching. This characteristic has been exploited by humans for millennia to obtain perfect long fibers uninterrupted by branch nodes. Close planting also results in only one large main cola where a phenomenal amount of seed is easily accessed and processed. Similarly, when a plant is in too small a pot the same hormones are released fooling it into believing it is close to other plants making it want to grow tall with minimal side branching. This phenomenon is exploited in SOGing where only a main cola is grown on plants with little to no side branching.

When growing marijuana for recreational buds or therapeutically strong flowers the further plants are apart the better. Five square metres is the recommended minimum outdoor area per plant. The spacious root room encourages the plant to fulfill more of its potential. It establishes more vigorous side branches which have multiple sites for flower production. Correspondingly, a big pot makes the plant think it is at a distance from its neighbours so it will have a much bushier aspect. This growth pattern is ideal for modern manipulation techniques like mainlining and SCROGing. The extreme outdoor example, of course, is ten pound plants grown in 4,000 litre grow bags. Mmmmmm ... ten pound plants.

INDOOR OR OUTDOOR

There is no real formula used to gauge ideal pot sizes for your ganga apart from the biggest possible for your particular situation. Things vary indoors and outdoors. You have already considered how much space you have. What type of growing you are going to do. How much personal time you have available for maintenance etcetera. You already know the maximum pot size in which you will finish your cannabis plants, getting the highest yields of buds possible for your personal situation. If you are growing outdoors, ease of maintenance in the early vegetative stage should be considered before planting into your garden, giant pots or grow bags.

WHEN TO FIRST POT ON

Your cannabis clones have taken or your seeds are thriving and have a healthy white root ball. You can see roots emerging from your rock wool starter blocks or jiffy pots. They may be starting to snake their way out of the bottom of your cloning trays or are in plain sight in your quick rooting or atomizing box. If the roots have already started to feather then be swift and gentle, you are running late. The feathering is very delicate and will break off easily. You want glossy white seeker roots. These roots are quite strong and they will easily penetrate the new medium before divaricating on their search for moisture and nutrients. At this point potting on is as simple as filling your chosen pot with growing medium. Make a hole with your finger in the centre and plant your seedling or clone. Back fill gently and water into place.

WHEN NEXT TO POT ON

A clone or seedling potted into a four litre pot will easily be ready for its final indoor location after three weeks. For this whole stage your marijuana plants will be easy to manage with no risk of water logging. There would be no need for an intermediary pot size. Outdoors roots will expand rapidly when given more volume. A four litre pot when potted on with minimal root damage will fill a nineteen litre pot within three weeks. For this whole time they are easily maintained with minimal effort after which they are ready to be potted on again to their final outdoor location. You will need a trusted friend to do a good job of transplanting from a larger pot. They are heavy and struggling on your own is a guaranteed way to do some kind of root damage.

HOW TO POT ON

The mantra here is " Transplant shock is bad. The less root damage the better."

First, water your plants thoroughly and leave to drain well for a few hours. This way the medium will be less likely to collapse when the pot is upended. Overly dry or saturated root balls collapse easily.

Gently squeeze the pot with both hands. Apply even pressure to each point of the compass.

With fingers placed either side of the stalk, palm flat on the surface of the grow medium, turn the pot completely upside down and make sure you have it balanced well.

Lift pot away to reveal the root ball. Timed to perfection a well-formed root mass will hold all the medium in place in the shape of the pot and not sag or break and fall apart. The roots will be bright white and not have feathered too much or have knotted at the bottom. If the roots are slightly yellowed and the root mass is very dense then you are a bit late but richer in experience. If the grow medium slumps away exposing seeker roots to the air then you are too early, but again, richer for the experience. In this instance delay your potting on for a few days so the rest of your weed crop can develop more roots and avoid being traumatized.

Fill your target pot close to full with moistened medium. Make a divot for the transplant to stand up in while you gently back fill around.

Water with the same amount used for the smaller pot for at least two days to avoid water logging the soil while the roots grow. Slowly increase the amount as the root ball and plant get larger.

WHY NOT POT ON TO THE BIGGEST POT FROM CLONE OR SEED?

This is up to you. The only issue is the risk of water logging soil that is yet to be invaded by roots. Use care when watering so as to not water log the bottom of the pot. Roots will recoil from saturated soil and be prone to rot. Leaves will curl under and growth will slow. Cannabis likes dry feet, so err on the side of caution. Water sparingly in the first week after potting on if you choose to go to the biggest pot immediately. You must consider though that in the early weeks of vegetation smaller pots are easier to look after. During those initial weeks well maintained marijuana plants have a substantial amount of attention paid to them. Small pots are easier to move about when tending and can be easily rotated to give 360 degree light coverage.

WHEN NOT TO POT ON

If you are growing autos put your sprout straight into the finishing pot and carefully increase water levels. Days are precious with autos. Four days recovering from unintentional root damage can be 6% of the grow time. That's 6% less dry yield at the end of the cycle.

A FEW NUMBERS TO CRUNCH FOR YOUR GROW

As a guide to help you utilize your space and time efficiently here is a list of standard pot sizes. A very reasonable plant can be grown in a thirty centimetre pot and an exceptional plant in a sixty one centimetre pot. All standard pots are alike in that their diameter at the rim is equal to their depth. A healthy cannabis plant can easily have a canopy three times the diameter of the pot.

Clone in chosen cloning medium

10cm pot = 4 inch pot = pint = 0.5 ltr

13-15cm pot = 5-6 inch pot = quart = 1 ltr

18-20cm pot = 7-8 inch pot = 1 gal = 4 ltr

22cm pot = 8.5 inch pot = 2 gal = 7.5 ltr

25cm pot = 10 inch pot = 3 gal = 11 ltr

30cm pot = 12 inch pot = 5 gal =19 ltr

36cm pot = 14 inch pot = 7 gal = 26 ltr

41cm pot = 16 inch pot = 10 gal = 38 ltr

46cm pot = 18 inch pot = 15 gal = 57 ltr

61cm pot = 24 inch pot =25 gal = 95 ltr

76cm pot = 30 inch pot = 30 gal = 114 ltr

Happy growing!