If your minimum temperatures in winter are 19C you won't have any problem repotting the plant any time. The longer you leave it the larger those roots outside the pot will become and the more likely to be damaged during a repot.

Boris is very pot bound right now. If allowed to stay in the pot much longer, he will litalaly break it open.

Thanks for your feedback! I will repot him on Friday! Fingers crossed he won’t be too traumatised :)

I agree w/ Robin & was going to suggest the same thing. It will not damage the plant, I assure you.

Just don't water it for a day or 2 after the repot.

You have to water a plant very well right after you have finished the re pot.! Why? To avoid air pockets near the roots. It’s known as “watering in”.

But I agree with cutting roots flush with the bottom of the pot. Less damage will occur that way.

My ZZ plant, when I got it, was in such a overgrown its pot as yours. I did wash the roots completely and pot it up in a pot that was 4 times bigger than the old one; 40cm in diameter. As the media I use fairly coarse orchid mix, with bark and coal, no moss what so ever. Ph in the bag says 5, so it's pretty acid, and as for fertilizer I use regular osmocote one, slow release fertilizer. Watering approximately once in the month/three weeks, in the shower. I got the plant last fall in september and re-potted it right away. Last winter it spent near the northern window and it has tripled or quadrupled its size. Now after we moved to a new house, it stays in the room with large windows facing both north and west, so I hope it will kick in growing even more. Longest leaves right nos are no less than a meter long, firm, solid dark green ones. Although my kids have ripped of a few leaflets so it's looking a bit messed up.

It will need a re-potting in a even bigger pot(I would guess a 40 litre pot will be good) in the spring, as the roots are growing out of this pot too. Just after a year!! Biggish, finger sized roots.

So, I've had a pleasant experience with our ZZ plant so far!

Lily,

Normally I'd agree w/ you abt watering in newly repotted plants, but not succulents, which a ZZ most definitely is.

I collect succulents & we don't water them in as it increases the likelihood of root rot.

The same thing can be accomplished (eliminating air pockets) by just banging the pot down hard a time or 2 against your table or potting bench. Settles the soil & knocks out air pockets w/ no risk of root rot.

So again, no watering in after repotting since you'll be cutting off the roots outside the pot, just wait a day or 2 before watering.