I used my drill motor with a 1" flat boring bit. The size of the pot might determine the size of the hole and how many.

Ploomer, thanks for the help! Can you drill the holes by yourself? Or do you have a helper hold the pot? If you do it yourself, how do you keep the pot and drill-bit from slipping around? I have been trying to figure out how to stabilize it or put it in a vice grip, but don't have an idea yet.

For the number of holes question: I am planning to use 5-gallon inner pot inside 7-gallon outer pot (as recommended numerous times on this forum). How many holes in a 5-gallon pot?

Drill as many as you can. If your drill is slipping around, take a small drill and make holes where the centers of the larger drill holes will be. If you have a Dremmel tool that little volcano shaped bit is great and is also great for making holes in plastic water bottles used in starting cuttings. Don't drill any extra holes in the 7 gallon. You want many holes for the roots to grow out of the 5 but keep most confined to the 7 until cut in the fall. The reason you cut holes in the side is that the key hole saw will easily cut the roots coming out but if they grew out holes in the bottom you would have complications.

I use my Dremmel to make a ring of small holes then push the circle out with my finger. The Dremmel is easier for me to handle then a regular size drill with a large bit.

Thanks for all of the help! I guess it doesn't matter if the inner pot looks like swiss cheese, because there will be soil mix in both pots(?). I'm guessing the soil will not spill out of the inside pot. But how about when you lift it? - don't you get soil mix all over your garage or wherever you store your plumeria for the winter?

Are your 5-gallon and 7-gallon pots the same height? Do you put any soil in the bottom of the 7-gallon setting in the 5-gallon? Or does the soil only go around the sides?

The same height is best. No soil in the bottom so the pots sit bottom to bottom so roots are discouraged to grow under the 5 gallon. When fall comes, most ot the holes will have roots growing out the holes and when cut off form the outside, they hold the soil in. Next year, new roots grow from the cut roots anyway. After you cut the roots and remove the 5 gallon with the plant, you can pull out the cut roots and soil mix and remove the roots, or use new soil mix the next year. You can leave the 7 gallon with the mix in all winter and remove ithe soil and old roots in the spring when ready to set up again.

Fantastic! Thanks for the detailed answers. Just one more question. What order works best for sinking the pots: dig the hole in the ground for the seven-gallon pot, place it in the ground, insert the five-gallon pot, then add the soil in between the two pots? Or combine both pots and soil, then dig hole in the ground and place the whole thing? Maybe it doesn't matter...

The first is easier to move around but it does not matter. If you leave the 7 during the winter, you clean it out in the spring, place the five in and fill around between the two with new soil.

I'm thinking of doing what you do tdogdad. But have a question. Can I keep on cutting the roots and leave the plumeria in the same pot every year, even as it gets larger or will I need to use a 7 gallon for the plant and a 9 or 10 gallon for the outter pot once the plant grows larger?

Thanks,
TJ

You can use the same pot but after time the pot will crack or split. At this time cut inside the pot and put in a new five gallon.

Here's what I use. It's just a wood bit and comes in diff. sizes. 1/2" or 3/4" work well. The sharp point makes it easy to start the hole.

The easiest way to make holes in a plastic pot is to use a soldering iron. Just let it heat up and apply.

Hope this helps.

John

Cool idea! Will it make a plastic mess all over my Dad's soldering iron? Or will the plastic just curl back from the heat?