Hi, Can someone recommend the best type of soil/substrate to use for maples in containers? A commercially available one would be great. I live in the Bay Area, CA so if there is a local nursery that sells their own mix, that would be great too. Thanks in advance for your reply and assistance!
Hi, shishi, not to be stingy with providing info, but try first the search engine for the maples forum. You'll find lots of info. Then you can still come back, and ask for clarifications. Here, for instance, is one I remember that helped me a lot http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=10132 But there is more info.
Hi Shishi, I was using Whitney Farm's Cactus Mix for my potted maples. I recently switched to Sun Gro Horticulture Black Gold Cactus Mix. You should be able to find it in your area. I switched out of necessity because the place where I got the Whitney Farm's switched to Sun Gro. I was pleasantly surprised by the Black Gold. I think it's just as good if not better. I like the fact that it has red cinder. Here's a discussion on it: http://www.botanicalgarden.ubc.ca/forums/showthread.php?t=12774 Layne
Hi Layne and Schusch, Thanks for the info. I will look around to see what I can find available in my area. When is the best time of the year to swap out containers? After the leaves fall or before the leaves come out in Spring? Thanks again!
If you repot, in the Spring. If you put in the ground, in the Fall. (But then again you live in SF Bay, and me in Continental Europe... I try to plant in the ground a few weeks before freezing temperatures.)
Hi, I would say that being where you live you could repot any time of the year as long as temps don't spike above 90 degrees. I LOVE the weather in San Francisco. Living there certainly makes raising potted maples a bit easier weatherwise. It never gets too hot or too cold. I get the Sun Gro Hort. Black Gold cactus mix at Anawalt Lumber here in Los Angeles. Don't know if they have stores where you are, but you could inquire at Sun Gro where their product might be available in your area. Layne
Add a lot of grit and small (aquarium) gravel to the mix - cactus soil can be mostly peat, which will not drain fast enough at all for maples.
Hi Rima, The Sun Gro Black Gold cactus mix doesn't have peat. I tend to advise against using grit/sand for maples. While not detrimental and it aids in drainage, it doesn't offer much in the way of moisture/nutrient retention and aeration. If you can try and find some red or black 1/8" cinder in your area. The cinder is great for drainage, aeration, moisture/nutrient retention and root ramification. Layne
If you use the right stuff, it'll add plenty of those things - 500 bonsai experts can't all be wrong, and they use no 'soil' at all in their small pots that definitely need moisture retention and nutrients even more than in-ground trees. Things like Schultz Soil Conditioner aka turface ((HIGH-fired clay bits that only look like old fashioned LOW-fired kitty litter that would turn to mush if used) -, crushed lava rock, pumice, perlite, chicken-grit from a farm feed store, etc. Then add in small sized bark mulch bits and you're done. Never have to worry about too much rain, and feel free to fertilize properly.
Hi Layne, I have started to repot my container maples and have bought the Black Gold Cactus Mix but it doesn't have the "red cinder/lava rock" in it and actually have pieces of the typical white pumice in it instead. The Black Gold Cactus Mix looks really loose and seems like it would drain well. The mixture I use is 50% Black Gold Cactus Mix with 50% Fine Grade Wonderbark Orchid Bark. Any comments or suggestions are greatly appreciated. Thanks!
Hi Shishi - it's all good in my opinion. If you are mixing the soil Layne recommended with more bark, you should be fine. As regards fertilization, it looks to me like you could go easy the first year in that new soil, especially on the nitrogen.
schusch, Why do you say "go easy on the fertilization in the first year with new soil"? Is this because you don't want to stress the tree as it may have lost some feeder roots during repot? or is it because most potting soils usually contain some fertilizer mixed in? I read another of your post where you were asking about using lava rock in the potting mix, any findings on that? thanks, xman
Hi, xman - I was thinking about fertilizer being mixed in, or otherwise present in fresh soil. (Rima is referring to an inorganic mix, where you might have to add more fertilizer.) I haven't been able to source lava yet, but will try again this spring. Schusch
I just bought a box of Foxfarms JM fertilizer and plan to use one application at half recommended strength this season for my container JMs that I have repotted but after reading your comments, I may hold off until next season. What is specific reason behind not fertilizing newly repotted container JMs? Thanks Shishi
Hi, Shishi - i don't know what's in the Black Gold Cactus mix in terms of initial fertilization. I'd ask Layne: she knows the product pretty well, as far as I remember - and take it from there. You can find good discussions of fertilization in this forum. Rima was mentioning non organic mixes, using grit, turface, etc - there initial fertilization is low, and you need to supplement for sure, but if you use a commercial mix that has initial fertilization, I'd go real easy in this coming spring, and only fertilize in the fall, may be, with a non nitrogen formula (but again conservatively). Schusch
Shishi, This is the contents of the BG cactus mix as sent to me by their soil lab Pumice(Screened), Bark(Aged Fine grade),Sawdust, Planting Mix (Fine Bark & Composted Humus mixed),Earthworm Castings, no fertilizer xman
This sounds like an interesting mix - no fertilizer added, but of course earthworm castings counts as an organic fertilizer and the forest product is not neutral. I'd say that counts as, at least, the initial nitrogen supply. Mixing it up with more bark, like you do, is probably the way to go, especially if it rains a lot. The younger your tree, the more you want it to develop a solid rootsystem - the more you might want a well aerated-light mix, with plenty of bark.
Xman: Thanks for the breakdown on the composition of the BG Cactus Mix. Schusch: Thanks for the confirmation that mixing in 50% of Fine Grade Orchid Bark is the right way to go. I will refrain for fertilizing this season to see how the trees react just to the new soil alone. The FoxFarm fertilizer has a production date stamped on top, do you know if it has a shelf life or expiration date? Thanks
Hi, Shishi - I do not have an answer to the shelf life question for organic fertilizers - may be someone else can jump in ? You could ask the company. There are a number of discussions about potting soil for maples here - check them out: it's best to understand the reasoning behind the recommendations, because ultimately you'll have to decide what's best for your maples over the years, based on observations. It's been my experience that maples do not respond very well to stress (too much or too little water) - not that they immediately die on you, but that you need to try to prevent the outbreak of disease. The 'soil science' info is very valuable in this respect, since a good mix makes watering easier. Schusch