Understanding pH for potting soil

Make sure you test your manure before spreading it lovingly on your blueberries! I did that one year… covered my blueberry area with composted horse manure, imagining all that vigorous, healthy growth. What I got was yellow, chlorotic leaves and a stall-out on growth. I finally meter-tested the manure … pH 7.8… way too high!
I finally dug up the blueberries and replanted into native soil with native mulch- and bushes took off again. Close call!

Yeah I don’t use any manure with blueberries. I pretty much only use Hollytone, maybe a boost with soluble once a month if I remember?
My harvests are very good, I still have some frozen. I think I have 13 plants now, enough I forget how many!

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They look great!

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To begin with, and most importantly - your blueberries look amazing, make me hungry, and bring back memories of picking blueberries out in Oregon! I always hear they won’t produce here, and will eventually try and learn for myself.

I think you mentioned at some point/somewhere that you don’t have many of your trees in containers. In my case I’m going to be putting 3 trees into containers to attempt to stretch seasons. As much as I’d like to try the fabric containers, I feel like I will have issues with them drying out (arid, windy, intense sun), and was also hearing from one mfg that with their classic (full fabric side) products, they were finding moisture wasn’t making it all the way to the bottom. Down side will be the root pruning, etc. But, given they will get moved around a lot, probably better for the plant. So, I will go with the barrels… cutoff at maybe 40-ish gallons.

Fabric containers seem really good on the smaller sizes. I am going to have to give these a go for some plants.

I’m going to give your soil recipe a shot, or some variation. Compost from the landscaping yard comes in at around pH 7.9 (specs say yard & food waste) or pH 8.6 (specs say wood, biosolids, some treatment plant residuals). My city water tested tonight around maybe 7.9 +/-, which isn’t too far off from yours (report from 2 years ago said range of 7.6-7.9). Do you think the 8.6 or 7.9 is better for the mix and my use? I think I am hearing your approach is to start on the low end of the range, given it will turn more basic with tap water, over time.

On the 1/4" pine bark fines, it sounds like they have bark pebbles, though they didn’t know if they were pine. Do you know if these sound right, and if they are usually pine? I might need to make a trip down just to have a look. Too bad I don’t have the time to make my own, as I have a big-ol pine that recently came down in my front yard.

Given how hot, intense-sun, and arid it is here, I’m thinking I might bump up the DE to be in the 20-25% range, unless you have concerns. It would be nice to be able to be gone 5 days without worrying too much about the watering. From what I can tell, the optisorb has a pH of 6.5.

Correct. A few I do, more to experiment. Most though are in ground.
As far as fabric, yes they dry out fast and trees soak water. I use 30, or 35 gallon bags. I have never had a problem with dry spots in bags, but have heard of it happening. I use them to leave out all winter, and also they are much easier to move.
I’m getting too old to move heavy pots. Another plus because of air root pruning, a 35 gallon fabric has the same growth as in a 70 gallon pot.

I don’t like small sizes. I buy nothing under 10 gallons. Way too dry, hard to reuse. I don’t like to reuse them. Roots grow into the fabric and are a PITA to transfer plants out of. With the bigger ones. I keep the plant in them until the bags fall apart. At that point I cut the bag away, easy peasy. I then usually up pot at that time. Root prune too. Depends, trees I start in larger fabric bags and may just root prune and put in new bag with new soil.

On pH of compost I would try the lower at first. Although you can mix with peat to knock it down, sulfur etc.

No that’s fine.

It could be hardwood, ask, they should know. Pine bark is hard to find that is just right. The bark I use is too fine, once in awhile I find perfect bark, if not I go to this finer stuff. Still works, just doesn’t last as long.

I guess by smaller, I was thinking size one person can lift. I feel like 30+ gallons starts to turn into one that sits on a dolly.

How are you using the bags?

When I called, they seemed pretty clueless. I think I’ll have to go have a look with my own eyes. Sounds like I should only be considering pine, not any hardwood bark.

It will not hurt to use hardwood but it will compost in one year. It may lock some nitrogen up too. So add a little extra. Pine can take 3 years also pH is lower with pine. Also does not lock up much nitrogen, only if bark is not composted does pine use nitrogen. I would not get too hung up on pH. Most plants grow fine in basic conditions.
I use pots for smaller containers. Plants outgrow them fast. I use fabric for everything. Figs, peaches, mulberries, pomegranate, blackberries, orange trees, other sub tropical fruit. Peppers and tomatoes, some in ground too. Potatoes only in bags. Red, black currants, gooseberries, black raspberries, and blueberries some are in raised beds. Some blueberries in containers.

It is interesting the op asks about “Home Brew.” I use these test strips when brewing meads. Never thought to test/adjust my blueberry row.

Ok, noted on the hardwood. Given where we are (rockies), I cannot imagine is is not pine… I will go look.

The reason these trees are going in containers, and not ground, is for season stretching, and to supplement the in-ground trees. It is common to get late frosts and freezes here and not get anything for the year, and likewise early freezes for late harvest. So my containers will be moved around a lot… mostly on dolly, but would not be unheard of to move them off hard surface, which will get difficult with the large fabric pots.

On your comment on fabric containers… are you suggesting, that despite the drying issues in our arid climate (there will be times I can’t tend to them for 3-4 days), and despite the challenges moving the containers around, you are thinking it is still a mistake to go hard container? I feel like I’m in a 6 of one/half dozen of another situation. I’d probably go 40+ gal if plastic.

No I’m not saying it’s a mistake. I really can’t comment on your environment. I was just explaining why I use them in this environment. I have many large pots and use them when I run out of bags. Or for a better presentation if plant has some ornamental value.
If a dolly has a nice and long foot I find moving bags easier. Although at 35 gallons they are probably harder to move. Usually I only use them when I plan not to move them. I have some decorative pots that weigh about 15 to 20 pound empty. One is made with stone and weighs 50 pounds empty. These are difficult to move. The simple large nursery pots are nice to work with.

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Curious, Drew - with your soil mix, roughly what do you find the weight of a given size when they are damp vs on the drier side. Trying to understand what the weight might be on a 30 vs 45 gallon edition, both damp and drier.

A total guess…dry soil weighs around 40 pounds and about 50 wet for 30 gallons. Plus or minus 10 pounds. I can pick up a 30 gallon. A 35 gallon is so big I can’t pick it up wet. I still use a dolly for both.

Thanks for that reference, Drew!

My roottrapper bags will be here tomorrow, and have a lot of the optisorb DE on hand. Ready to plant! Re: DE - I did get to thinking about avoiding significant watering prior to harvest. I recall you also mentioned not having may of your trees on containers. Have you experienced, or would you have any concerns with, using 15-25% DE with the fruit trees in containers, and maintaining high sugars during harvest? I wasn’t sure if the extra water available during harvest could be an issue.

Interesting question, It should not be a problem. I would judge water amount by lifting the pot, one way to tell. The tree will drain the water out of the DE as it will the soil. Even with DE pots dry quickly and in this case the fabric container will also dry quicker. I don’t think you will have any problems with the DE staying wet. The time to dry will be longer, but fabric shortens time so it all balances out.
One major advantage to fabric is root temps. This can be a problem in plastic pots, not such much in fabric.

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Ok, thanks for the thoughts, Drew. Good call on hefting the pot to gauge dampness (though with fruit that may get a little harder).

With the roottrapper pots, given they use root trip trapping (versus air pruning) to create the healthy root system, the coating on the outside is not very air permeable, though they leave couple inch gap at the bottom uncoated (breathing and drainage). The less breathable sides (white) are one of the the reasons that here in our hot, arid climate I thought they would be a good pick.

Maybe I will keep to 15-20% DE and not go too crazy. I guess if I get to bearing fruit and the sugars aren’t very high, I can look to do some root pruning and change the soil mixture a bit, though once you have a dense root ball, I’m not clear how easy that is to do.

Even if you can just lift one side, you can tell where it is.

OK, I was thinking they were something else, got it.

You can hose the soil off of root ball and see them better to prune. One does need to try various things to see what works best.

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