When to replenish gypsum for blueberries in containers?
Larry (Los Angeles, 10a, Sunset Zone 19)
7 years ago
last modified: 7 years ago
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container blueberry
Comments (9)Hi, Groem - neat forum name. ;o) Lots of people have grown BBs in the 5:1:1 mix, and it does work very well. BBs are like potatoes - they like lots of moisture, but don't tolerate wet feet. I would probably use the gritty mix and plant them in very large containers, but that's just my personal preference. If you wanted to change it up to benefit your plants more, you could use a 5:2:1 mix of PBFs:Turface:peat, which would offer better water retention with no sacrifice in aeration/drainage or the ht of the PWT. The gaps in the boards won't do much to help drainage or aeration, but it won't hurt anything, either. It might be a good idea if you didn't let the roots escape into the surrounding soil through the container bottoms because it SOUNDS like there would prolly be some significant pH issues involved if that occurs, in your area. I've never heard that BBs don't like their roots being mauled. I don't grow them, but I have a lot of friends that do, and I've helped them (and a lot of others) manage their bushes. To date, it's the first time I heard that comment. *Root pruning is what it is, and WHAT it is, is a way for you to eliminate the crowded conditions and root problems that reduce growth/vitality/yields in your plants. There is no such thing as 'going to a bigger pot so I don't have to root prune". You HAVE to root prune to maintain plant health/growth in containers. There is no way around it, unless you ALWAYS pot up before roots get so tight the root mass & soil can be lifted from the container intact. Mess up once & ignore potting up, letting roots get tight beyond that point, & you need to go back to the asterisk above & reread. ;o) Here's how I would manage the Ca/Mg thing. Add gypsum when you make the soil. Then, include 1/2 tsp Epsom salts to the fertilizer solution each time you fertigate. If you leave the plants in the same soil for more than 2 years, reapply 1 tsp gypsum per gallon of soil in each subsequent year & keep using the Epsom salts. I would also get a pH test kit and determine how much vinegar or citric acid it takes to lower your tap water to a pH of about 4.5. Don't worry, as the water gives up it's CO2, the pH will rise by about .5 to around 5.0. You'll have really nice plants then. The 30-10-10 is much higher in N than it needs to be, so you might consider reducing your application rate & adding in a K supplement like Pro-TeKt 0-0-3, essentially turning your 3:1:1 fertilizer into a 3:1:2 ratio. Alternately, just use 24-8-16. The acid reaction in Miracid or azalea fertilizer (30-10-10) comes from the fact that the N source is urea. As urea breaks down, it releases H gas (the 'H' in pH) which lowers the pH of the soil solution and soil. 24-8-16 is ALSO an acid-forming fertilizer - they just don't put it on the label because they want you to think that 30-10-10 is essential to plants that do best at lower pHs - the dirty tricksters. Don't use fertilizers that get their N from nitrate sources, including FP fertilizers, (I hope our fertilizer watchdog heard that) and please don't add fertilizers that contain urea at mean temps below 55* - to guard against ammonium toxicity. Lol I don't particularly like adding S to container media to reduce pH because there is already enough S in the soil. All proteins contain SOME S, many fertilizers contain sulfates, and acid rain also provides it. You'll probably be using MgSO4 (Epsom salts) which also supplies sulfate. Sulfur under anaerobic conditions produces H2S (hydrogen sulfide) gas that is toxic to plants. It's better to manage pH by managing the pH of the soil solution - which is the most important consideration for container culture. Ruth - the soil (gritty mix) will assuredly hold up for 3 years or longer. Let root congestion be your guide to when repotting is appropriate. Click me to go to another good thread about blueberries. .... and if you're still interested, you can click on me, too. Al...See MoreQuestion about blueberries in containers
Comments (48)Regarding the lack of availability of pine bark: I went in to my Home Depot three times asking for it. Their computer showed they had 75 bags of it but nobody would help me find it. Finally one worker said. "Don't use pine bark -- it will kill all your palnts." I told her that it was ok, I want acidic bark for blueberries. (No reaction.) They still wouldn't find it for me. Maybe they really believe its bad for all plants and that's why they don't put it out. I noticed that all five kinds of the "bark nuggets" they do sell are all just wood shavings not bark, and are all dyed. Yuk. I'm glad to hear that Lowe's carries pine bark! Thanks....See MoreHaving trouble maintaining low Ph with container blueberries
Comments (3)My suggestion is to worry more about where soil solution pH is as a generality and less about chasing a particular medium pH, which I'm absolutely sure will end in frustration anyway. If you use a fertilizer that derives its N from urea (not nitrates) and neutralize your irrigation water's alkalinity with vinegar if you suspect or know alkalinity is high, you'll be just fine. Container media pH is nowhere near the issue that the pH of mineral soils is. From something I left on another post: BBs have some pretty unique nutritional requirements compared to most other plants. They grow in acidic soils where fertility is usually quite low. Also, the predominant form of available nitrogen (ammonium) is usually present at levels that could be toxic to many plants. However, BBs have mechanisms to cope with the acidic, ammonium-rich, nutrient-poor conditions. They form a symbiotic relationship with certain fungi, which derive carbohydrates from the inner portions of the BB root system, and in return, help extract nutrients (especially phosphorus and nitrogen) from the soil for the plant. So, in comparison with many other plants, BBs have very low nutritional requirements. In fact, they can be quite sensitive to high levels of some nutrients, and a heavy fertilizer application can injure them, so be sure you fertilize at reduced recommended strengths (1/4 - 1/2 strength, weekly to bi-weekly). BBs also have the unique ability to directly absorb ammonium ions. Most plants absorb N in nitrate form, which is then converted to ammonium by a metabolic process before being incorporated into proteins. However, nitrate fertilizers can be harmful to BBs. For this reason, ammonium forms of fertilizer are recommended, such as ammonium sulfate or urea. Ammonium sulfate is particularly good because it acidifies the soil, and most soils tend to have a pH higher than 4.5. (Foliage-Pro 9-3-6 offers 2/3 of its N in nitrate form, which is normally a good thing, but not particularly desirable for BBs.) In another thread, someone made the comment that there is no Ca in fertilizers for acid-loving plants because they don't like it. JaG appropriately pointed out that ALL plants need Ca, which is true. The reason there is no Ca in most of the fertilizers we use on container plants is simply because of solubility issues. The fact that different species of plants tend to grow on different types of soil does not mean that the one needs more of a certain nutrient than the other. It just means that the plants have developed strategies to adapt to certain conditions. Acid-loving plants have adapted to acid soils. Their need for calcium is still the same as any other plant, and their nutrient requirements do not differ from plants that thrive in alkaline soils. The problem for acid-loving plants is that they have not developed a method to limit their calcium uptake, and will absorb too much of it when available, resulting in cellular pH-values that are too high. Some acid-loving plants also have difficulties absorbing iron, which is tightly bound in alkaline soils, another reason why they thrive in low pH soils. This all pertains to the plants ability to handle nutrients, not to the actual nutrient needs of the plant. Filix is concerned (remember, this is off topic slightly because it was addressing issues being discussed on another thread)about micro-nutrient availability if he uses the MG 30-10-10. It contains all the micro-nutrients that are likely to be deficient in container soils, but glaringly absent are the secondary macro-nutrients Ca and Mg ... S as well is missing. Supplying the Ca with gypsum and the Mg with Epsom salts is probably the best plan. Though insoluble, enough S can be had by including a tsp of elemental S per gallon of soil. Al...See MoreDoes lime in 5-1-1 mix need replenishing?
Comments (6)If you use foliage pro then it adds both Ca and Mg to the mix. If not you will have to add those separately from time to time. I do fertilize with Epsom Salt since Mg leaches out much faster than Ca. Ca will be held a little longer in the soil. I am not a soil chemistry expert but from what I can gather is that the initial liming is to neutralize the acidity of the 511 mix and bring it more towards neutral. So here goes some of my thoughts on this. Mineral soil (clay based) have a much better buffering capacity and thus resist changes to Ph. Compost/humus also aid in this process. Sandy soils have the least buffering capacity. Bark+peat based soils do not have that buffering capacity and so the initial lime helps. Also residential water tends to be alkaline and so that does some additional help in keeping 511 more towards neutral. Rain, on the other hand, tends to be acidic (dissolved CO2). Gritty mix has lot less bark and no peat and so it is less of a problem. Plus the turface probably increases its buffering capacity. May be granite grit does too to some extent. I always make gritty mix with gypsum and Epsom for the Ca and Mg components whereas my 511 is always with lime. Keeping this thread alive and may be one of the experts on this subject will pipe in....See MoreLarry (Los Angeles, 10a, Sunset Zone 19)
7 years agolast modified: 7 years agoLarry (Los Angeles, 10a, Sunset Zone 19)
7 years agolast modified: 7 years agomyermike_1micha
7 years agoinkfin
7 years agoAnthony
7 years agoinkfin
7 years ago
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