Why translant from small to big?

I currently have been transplanting from smaller to bigger pots as the plant needs it. I figured that I could use the space but also it cuts down the possiblity of over watering and nute build up.

I was just challenged of my methods of madness and was wondering if there was anything I missed?

Most growers transplant from tiny 4" pots to 3 gallon pots 2-3 weeks after seedling, their the plant stay, if you grow longer than 3 months use 1 gallon of soil per month ..the plant is alive, ie, 6 month plant equals 6 gallon pot.

peace
"V"

I know was just looking for other reasons why to transplant rather than going straight to the big one.

Root mass. If you fill say, a 16oz solo cup full of roots, you have a large center root mass for the plant to expand and grow out of after transplanting. Example is my white widow, if you look at my grow, after it went from solo cup to 1L pot, it literally exploded with new growth within days of recovering from the transplant shock.

Transplanting up is really only necessary with plastic pots. Starting in a small pot and transplanting up ensures that you fill the whole soil mass with roots. If you started a small seedling in a large pot, the roots would just grow to the side and start wrapping around, totally missing the middle.

This can be totally avoided by using fabric pots or any type of aeration container. They also prevent root rot and root binding.

Root mass. If you fill say, a 16oz solo cup full of roots, you have a large center root mass for the plant to expand and grow out of after transplanting.

I have always heard this as a reason for transplanting but have never believed it. If the roots have a large soil volume available to them from the start they will grow to fill it out just as well, just as quickly.

To the OP, the questions is backwards -- not why transplant to larger pots (which would suggest that it might be OK to leave them in smaller pots through the whole grow), but rather why plant in smaller pots to begin with, if you are only going to put them into larger pots later? Why not just start them in larger pots?

The main reason is simply better control and a little lower cost. Little sprouts can be hard to water properly when they are in big pots, it's hard to tell when the soil that the roots can reach dries out (in a large pot most of the soil could be damp but up top near where the young roots are it could be dry). You also have to deliver nutes to the entire soil volume, so a baby sprout in a large pot wastes nutes.

But you can start in larger pots, no specific reason against doing so as long as you can manage the watering and feeding i the first few weeks.

Most growers transplant from tiny 4" pots to 3 gallon pots 2-3 weeks after seedling, their the plant stay, if you grow longer than 3 months use 1 gallon of soil per month ..the plant is alive, ie, 6 month plant equals 6 gallon pot.

peace
"V"

Exactly what I do, but around 3-4 months I transfer to a 8-9gal pot since im going 6-7 months total time.

I tend to see root activity breaking the surface at 4 months/5gal and then again near the end of the cycle at 6.5 months/9gal. another good reason to transfer.

Edited by wwpk, 26 August 2012 - 05:55 PM.
more info added

There are a few reasons why it is common practice to start with small containers and move up to larger containers as the plants roots fill them.

The main reason is water management, if you had a small seedling in a 5 gal container then the roots would not be able to reach the vast majority of the soil to absorb nutrients and water so the soil in the outer and lower areas would stay wetter than the area around the rootball.

The roots will eventually fill in the container but the rootball will not be nearly as dense as it would be if you started in smaller containers.

Another main reason why newly seeded or cloned plants are planted in smaller containers to start off with is it is much easier to manage a few dozen clones if they are in quart size containers than if they were all in the final large containers.