Hi, I'm new.
I have had a sageretia bonsai for about 18 months. Just over a month ago I repotted it for the first time. For the first 2 weeks or so after repotting it looked shocked and the leaves discoloured. Now it's looking really healthy, it has new leaves growing all over which have red tips.
My concern is the soil I used when repotting. I bought Lorbex bonsai compost from my local gardening centre (before I had read about such things as akadama).
The new compost stays wet for days after watering. Obviously I can adjust frequency of watering to accommodate this but I'm worried I bought really low quality soil.
Also the bonsai food I have recommends feeding every 10 days but with how long this compost retains water that would mean using fertiliser every time I water, would this result in too much nutrients building up in the soil?
I'd appreciate any advise you can give on whether I should be concerned about my choice of soil and how often to use fertiliser.

Thanks

Hazeltree wrote: I bought Lorbex bonsai compost from my local gardening centre
The new compost stays wet for days after watering.
Also the bonsai food I have recommends feeding every 10 days

I'd appreciate any advise you can give on whether I should be concerned about my choice of soil and how often to use fertiliser.

You're doing it completely differently than (most of) us, who grow our bonsai outside, in a well-draining soil.
Overwatering is hardly possible, as the soil drains freely. Overfertilizing will not occur easily, as excess fertilizer is flushed out. To be honest, I cannot give you much advise, as, well, I have no experience growing plants this way.

However, you write the plant is doing great, so you must be doing a good job. Continue with that

For fertilizing, follow the instructions on the bottle.

Thanks for your reply.
Does anyone else have any advise for me?

Hi.

I guess you cut too many roots when re-potting. That would explain why your soil is staying wet too, as the tree is using its energy to build new roots. I doubt the soil is the problem. Also, if it hasn't been sunny and hot, don't expect the soil to be dry. Put the tree on a shaded area while it recovers, and make sure to mist the leaves twice a day. The tree can't use its roots to feed, as it has just been re-potted, but it can "drink" from its leaves.

In terms of feeding, don't feed the tree now while it is recover, let it recover first. When you see your tree is looking better, you can use a very mild fertilizer mixed with water (like organic fish fertilizer). Use VERY little, and let the tree recover. Once the tree looks healthy and vigorous, move to a more sunny area, put some slow release fertilizer, and compliment with the fish fertilizer every two weeks. This fertilizer approach was told to me by a professional bonsai artist, and it seems to work really well.

In terms of soil. there's not much you can't do at this time of the year, you shouldn't repot the tree if you don't like the soil. Give your tree some time, if the soil stays too wet, and your tree doesn't grow as much as you'll like, you can remove as much as top soil as you can (DO NOT bother roots), and add some akadama, or pumice, or any fast draining compound. You can also use a chopstick to open wholes on the soil, so it drains faster. Then next year, re-pot with a different soil mix. I personally use layers instead of a single mix. I put a layer of small pumice on the bottom, then medium fir bark mixed with a little pumice very little compost, then at the top I use compost mix with med. fir bark and I top it with small river rock. the "Compost" I use is a rather cheap organic soil mix for trees and shrubs. This is working really well for me, and it is much much cheaper than akadama, or any "bonsai soil mix".

good luck!

Hi, thanks for your response. The tree looks very healthy to me, new leaves and shoots have been growing rapidly since I repotted, would that indicate that it has recovered?
I'm considering watering by submersion in future. last time I watered I left it until the soil was quite dry and it took several waterings to take water again and even then I couldn't be sure the root ball was wet because it wasnt absorbing well at all.
Would watering by submersion be a good way to sort this?

Here is a picture

No. Watering by submersion because the rootball stays dry, means you are not using a good substrate. you should look into bonsai substrate.

Water with lukewarm water instead of cold water. That will penetrate the rootball better, as it has a lower surface tension.

I know the substrate isn't good, I plan to use a different mix when I repot next spring but in the mean time why not water by submersion if it means it will definitely get the rootball wet?

The only times I do a submersion is in the initial repotting & during a dry emergency. In both situations, the soil is completely dry, and submersion ensures that the soil is completely soaked throughout. After that, regular waterings are all you need. The root ball just needs to be damp, not wet. Root growth does best in these conditions. Too much water, & you've created a swamp environment, which only certain types of trees, like bald cypress, will tolerate. Too little water, & you've got a completely opposite condition - desert & potential death of tree. Good draining soil removes most of the water, leaving it damp - which is the way you want it.

Watering from above helps flush out excess nutrients & chemicals. Excess fertilizer can burn the roots. Pesticides, fungicides, etc should only be used sparingly anyway. Decomposing organic matter, like compost or pine bark, can increase the pH of the soil mixture. Fresh water in and old water out alleviates this. If the tree is submersed, it's like swimming around in a pond that only gets topped of by rain. The waste & detritus & excess just keeps building up. Still using the pond as an analogy, if there's a stream running through it with fresh water and a means to exit like a top drain, then fresh is going in and waste is going out.

You've already said you let it dry out for a few days before watering again. Perfect. As Auk said, follow the instructions on the fertilizer - every ten days to two weeks is normal. Too much of anything, including water & fertilizer, isn't good. Water from the top, let it flush out the bottom. Your changing of soil next year will probably do the tree a great service. Keep it up!

Thanks for explaining the problems with submersion, that makes perfect sense.

I'm just concerned because last time I watered, the whole surface of the soil looked drenched but when I disturbed the soil to check it was still bone dry just under the surface even though the water was running out the drainage holes in the pot. I don't trust that all the soil is getting wet when I water.
I think it will just need extra attention until next year when I use a more suitable substrate.