JAG, can you elaborate on the idea that pH is not as important for blueberries in pots as in the ground? Al, do you concur? Yes - I do. Mineral soils in general hold nutrients much more tightly than the highly organic soils we grow in. If you'll consider: Even the gritty mix I often use is still highly organic at 2/3 inert ingredients: 1/3 (33%) bark as compared to the sandy soils the BBs are usually grown in with an extremely low organic component (usually Fertilizers affect media solution pH and make it easier/more difficult for certain types of plants to extract nutrients from soil solutions. Often, the plants themselves add ions to the solutions to actually change solution pH and make it easier for the plant to take up ions. The fertilizers we would want to use for blueberries will have an acidifying effect due to the ammonium nitrogen content. Fertilizers that form acids will be high in ammonium, ammonia, and urea. During nitrification, ammonium is converted to nitrate in the media, and in the process H is released which lowers pH. Plants also secrete H into the media whenever they absorb ammonium. Fertilizers containing nitrate in the form of calcium/potassium/magnesium/sodium nitrate all tend to cause an alkaline reaction and raise container solution pH. Although the most important factor in where media solution pH will fall is the alkalinity of the irrigation (which includes the fertilizers added) solution, it's not the only factor. We need to not only consider the fertilizer, but also the pH of the medium components, the liming materials used in the medium, and the pH/alkalinity of the irrigation water before adding fertilizers. Finally, the gritty mix should be fine for BBs if you use gypsum as a Ca source. You'll need to water fairly frequently if you use it, though. Turface and granite are both mildly acidic, and the bark will be around pH 4.5-5.0. Al

For one plant, buy the mix as suggested. But, peat moss doesn't have enough nitrate to bother (or help) the blueberry. So long as you are talking about the baled Sphagnum moss peat that is commonly sold in the compressed bales, not reed peat in regular bags such as fertilizer or most mulches and soils come in. That peat may or may not be OK for blueberries and it would be hard to tell without trying it. It could have too high of a pH. It also could be as high as 4-5% nitrogen, but not as nitrate.

What's the PH? It looks like it could be a fungus, but unsure? Leaves do turn when in trouble. Espoma Soil Acidifier takes at least 6 months to work. If PH is high and the plant is struggling it is susceptible to disease. It could be a nutrient deficiency, if so, it's from high PH. First thing is get that PH right. About 4.5 would be good. Once there, you can tell better. A quick fix would be to add vinegar, even better and permanent would be sulfuric acid. I use battery acid to amend my water.

There is NO reason to use a highly toxic organophosphate when Bt is so readily available. Bt, in combination with altering your watering habits, will fix the problem. Organophosphates include some once commonly used pesticides (like malathion), yet are very poisonous. They affect the mammalian nervous system upon exposure. They are cholinesterase inhibitors. Fumes, by the way, are a common avenue of entry into the body. Pets and children are at extreme risk, as are the elderly, the ill, or anyone taking medications that can affect the liver. Drenching potting mix with an organophosphate is never recommended. The chemicals will adhere to the organic particles (peat moss) for a very long time. So, dancinglemons, the drench that people are talking about in conjunction with fungus gnats is Bt. Many people buy a package of the mosquito dunks, break off some pieces to soak in the water for a while, then water as usual. Others buy a product called Gnatrol (found online). Use the Bt solution every time you water for a few weeks and the problem should be over. It is perfectly safe to use around you, your familiy, and pets. Unless, of course, you consider gnats, mosquitoes, and such as your pets! If you go over the Container Forum, you'll find several very good recipes for potting mediums that are almost guaranteed to be gnat-free. Your goal is to make a potting mix that is rapidly draining and very coarse in texture. I've not seen a fungus gnat in 20 years!