Is transplanting a waste of time?

I've never transplanted from a small pot up to a larger pot and I don't really see any benefit to doing so. I just start my seeds/clones in 2.5 inch Rockwool blocks and then after around 2 weeks I go straight into the final 5 or 7 gal cloth pots.



I know that a lot of growers swear that there are advantages to having the plant in a smaller pot and then transplanting up and I would like to learn more about what these advantages are. Using extra nutrients/water to wet a larger pot size isn't something I'm concerned about so would like to know what other benefits there are.



My reasoning for not doing it is that the root system is unrestricted and can spread out faster without hitting the edge of a small pot. We all know that the pot/root ball size is directly related to the plant/yield size. I believe that by having unrestricted space for the roots to expand I'm not sending any signals to the plant to slow down when it hits the edge of the pot. Also there's no stress from transplanting. Transplanting is a known cause of stress to the plant so why do it when we don't really have to?



I'm not saying that either way is right or wrong just interested what people's reasons are for using this
method.

@PopAndSonGrows to me that pic is kinda bro science. Is there any actual scientific reasoning to back up the theory?

I am of the opinion that there is no advantage to multiple transplants. Plants grown in the ground, where there is no restriction on root growth, get bigger than plants grown in pots, so to me, that's always been enough to convince me that root restriction is counterproductive.

But, I'm not a scientist and I've never done a side-by-side comparison, and things may work differently growing indoor where you will ultimately be growing in a container, as opposed to outdoor.
Transplanting may shape the roots to make them grow in a way that is more advantageous for growing in a container. Don't know, that's not something that I have to factor in when growing in the ground.

Kola_Kreator said:

@PopAndSonGrows to me that pic is kinda bro science. Is there any actual scientific reasoning to back up the theory?

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i had the same assertion once. Someone had the point that in the horticulture industry its a common practice to up-pot, and why would they be wasting their time doing that hundreds of times for certain flowers and other plants?

For one after a ton of waterings in the same container, your soil would get depleted faster, so a transplant would put your roots in direct contact with super fresh, non compacted soil.

Ive done it both ways and it DID seem like the times i skipped transplanting they grew slower, but thats far from concrete evidence.

Funkentelechy said:

Things may work differently growing indoor where you will ultimately be growing in a container, as opposed to outdoor. Transplanting may shape the roots to make them grow in a way that is more advantageous for growing in a container. That's not something that I have to factor in when growing in the ground.

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For me a healthy DWC root ball is clear example of what is possible when there is no space restriction or dry back to encourage roots to search for water

madvillian420 said:

Someone had the point that in the horticulture industry its a common practice to up-pot, and why would they be wasting their time doing that hundreds of times for certain flowers and other plants?

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In the horticulture industry, it's all about the number of plants you can grow and sell in a given space. So say you have seven greenhouses all the same size if you can start two thousand plants in one greenhouse, you grow these out and then transplant those into a larger container, then you have to transfer those into two greenhouses because they take up more space now with their larger containers. Then as those grow out you then have to up pot them and transfer the same plants that were previously growing in those two greenhouses into four greenhouses, because the bigger containers take up more space, yadda, yadda.
You can see in the end that it takes four greenhouses to house two thousand plants in their biggest containers. So if you started all your plants in their final biggest containers you'd only be able to grow 3500 plants total in your seven greenhouses, as opposed to 6000 if you were to continuously up pot.

Although, in addition to not being a scientist I am also not in the horticulture industry, so this is conjecture on my part.

In about a week I'll harvest my current grow. I'll drop some pics of how much the roots filled out the pots when I pull them.

Kola_Kreator said:

In about a week I'll harvest my current grow. I'll drop some pics of how much the roots filled out the pots when I pull them.

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And how will you know what the roots would've been like if you transplanted correctly?

The only way to tell is grow 2 side by side, with all conditions the same except the transplanting. And yes, people have done this, and yes, they have concluded transplanting is beneficial and worthwhile. However, those are the same people referenced in the post #2 graphic that you called 'broscience'.

Who are you going to believe, and why? What is your background?

Kola_Kreator said:

@PopAndSonGrows to me that pic is kinda bro science. Is there any actual scientific reasoning to back up the theory?

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It comes from water-only organic grows. When the pot is too big, Nitrogen gets washed below the roots and only a few chase it down. In other words, water based solely by plant size, don't try to force the roots to chase nutes washed to the bottom, it doesn't work.

Kola_Kreator said:

@PopAndSonGrows to me that pic is kinda bro science. Is there any actual scientific reasoning to back up the theory?

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Hundreds of years of gardening.

One of the points is to maximise root mass in the container.

Roots will naturally spread out and hit a wall.
They know they've hit a wall because microreceptors in the root can sense calcium and when there isn't any they change direction, which in a hard pot means they will travel around that pot, circling. So most of the root mass is on the outer extremities, until there's no more space, then they might go back in and follow the calcium.. problem with that is the original circling roots become thicker and then can choke off the others and essentially strangle the tap root.

This isn't as big of a deal with cannabis because they generally don't live long.
It's also not a big deal in a cloth pot because root structure is changed by air pruning.

But getting back to your question.
It's to maximise the amount of root mass in a way that's not detrimental to the plant.

That's one of the main reasons for potting up.

Too many variables to declare one way better than the other. Genetics, environment, medium, watering/feeding habits.

I never looked at it that way though. To me, it's logistics. Smaller/bigger pots are about controlling plant size.

Driver733 said:

And how will you know what the roots would've been like if you transplanted correctly?

The only way to tell is grow 2 side by side, with all conditions the same except the transplanting. And yes, people have done this, and yes, they have concluded transplanting is beneficial and worthwhile. However, those are the same people referenced in the post #2 graphic that you called 'broscience'.

Who are you going to believe, and why? What is your background?

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If the pot is full and root ball is dense I can't really fit anymore in there..

I couldn't find any documented side by side experiments if you know where to find one could you please post a link.

MtRainDog said:

Too many variables to declare one way better than the other. Genetics, environment, medium, watering/feeding habits.

I never looked at it that way though. To me, it's logistics. Smaller/bigger pots are about controlling plant size.

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Yes for sure. There's more than 1 variable. In my setup I have cultivars that I believe would not benefit from transplanting up through different pot sizes. I was just trying to gather more info on the reasons why some growers choose this method.

coreywebster said:

Hundreds of years of gardening.

One of the points is to maximise root mass in the container.

Roots will naturally spread out and hit a wall.
They know they've hit a wall because microreceptors in the root can sense calcium and when there isn't any they change direction, which in a hard pot means they will travel around that pot, circling. So most of the root mass is on the outer extremities, until there's no more space, then they might go back in and follow the calcium.. problem with that is the original circling roots become thicker and then can choke off the others and essentially strangle the tap root.

This isn't as big of a deal with cannabis because they generally don't live long.
It's also not a big deal in a cloth pot because root structure is changed by air pruning.

But getting back to your question.
It's to maximise the amount of root mass in a way that's not detrimental to the plant.

That's one of the main reasons for potting up.

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If up potting increases root mass why do we see such huge root balls on DWC plants?

The plants biological processes are exactly the same no matter which medium or method is used to grow. If the theory behind up potting is correct then why doesn't DWC produce small root balls?

Kola_Kreator said:

If up potting increases root mass why do we see such huge root balls on DWC plants?

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In DWC roots are suspended in water, not growing through a semi solid that they grow through.
So they float about directionless until there's a big enough root ball.
So there's no circling, roots don't grow hard either , so no choking off.

Feel free to try growing two plants in hard pots and experiment after harvest by washing all the medium away.

You'll see that not only is there more root mass but also a more efficient system because the roots are spread more evenly throughout the medium.

I always thought pot size was for more effective moisture control. I think it also makes a difference between running live soil versus soilless.
In soilless you want a full water with runoff to leach excess salts and avoid hot spots. In living soil you can do smaller waterings to slightly increase soil moisture.

7CardBud said:

I always thought pot size was for more effective moisture control. I think it also makes a difference between running live soil versus soilless.
In soilless you want a full water with runoff to leach excess salts and avoid hot spots. In living soil you can do smaller waterings to slightly increase soil moisture.

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I run Coco. And basically I never let it dry. Maybe my medium and watering habits is why I'm getting full root systems without up potting.