my concern was that the coir/peat/perlite mix may be too clumpy/muddy - i was hoping the perlite would break it up some. i thought of throwing in some humus and compost. thoughts on this? The trick is a mix that is always moist, but also supports good aeration. I think that the peat/coir/perlite will probably achieve that, but not for more than a season as they will begin decomposing and breaking into smaller sizes quickly. As this occurs the water retentiveness of the mix increases, but at the expense of air holding capacity of the mix. Compost and humus would likely make the problem worse. I don't know what humus is in this sense as the stuff sold in bags isn't what I consider humus, it's often sawdust like stuff from what I have seen, but haven't looked in a few years. Compost will also break down very quickly. What many growers use is pine bark as the basis of the mix. It also breaks down, but more slowly and it starts at an appropriate pH. Filix has reported good success with his blueberries in Al's 5:1:1 mix (5 parts pine bark fines, 1 part peat, 1 part perlite). If you are concerned about the suitability of any mix you can test it in a clear cup. Fill the cup with mix, saturate it with water and then poke a hole in the cup so the water can drain. After no more water is draining, look to see if there is a water layer on the bottom. This would be the perched water table and blueberries aren't going to like it. If you just have an inch or less and you are using a reasonably tall container it's likely not going to be an issue, but if you have much more than that you are taking a risk with the shrubs. Keep in mind the organic component of any mix is going to break down over the season and the PWT will increase in height as it does. Some materials break down quickly, others more slowly. so, justa, i've read many of your responses to BB/soil pH, and i welcome the difference of opinion that you and i seem to share - i find soil pH paramount, you don't seem to, rather you attain it via watering and fertilizers. It isn't that I consider pH unimportant, but rather it's next to impossible to control without continual monitoring. As you saw from the link you posted the pH of the mixes shifted throughout the test. With a quality fertilizer intended for hydro or container use many nutrients will be chelated and available to the plant even when the pH is out of normal bounds. Unless one has testing equipment and is willing/able to respond appropriately to control pH swings (occur quickly and are short lived) and shifts (a longer term movement) it's not really worth fussing over, in my opinion. Rather, by building a mix that starts out with an appropriate pH range, and neutralizing the alkalinity of the irrigation water via vinegar or using rainwater when practical there should never be a problem. Something to keep in mind is that the plants are getting nutrients from the water and whatever nutrients are dissolved in it, not (so much) from the growing media. If the pH of the water/solution around the roots is good, then the plant is happy too ;) BTW, are you a veterinarian? Just wondering due to your handle/name/alias ;)

All I can say about the PermaTill is that it comes in various sizes, and the size that would be best for making a mix similar to the gritty mix would be between 1/2 BB-size to BB-size. "Now, if I don't sift the pine bark fines out, does that just shorten the life of the pot?" If you're making the gritty mix and you don't sift the bark, or you use a product with a lot of fines, you sort of negate the whole purpose of making it. It's structural longevity and high degree of aeration are its hallmarks. If you start adding fine particulates to it, you might as well opt for the 5:1:1 mix or similar, because there would be little advantage in a gritty mix with lots of fines in it over any other soil heavy on fines. "Another question I have is whether this mix of pine bark, granite and turface is - is it suitable to growing all plants?" I have yet to try a plant in it that hasn't done extremely well. I don't use it for short term plantings like veggies and flowery display containers, but I use it for everything that might be in the same soil for more than a single growth cycle - all my woody plants and houseplants, including cacti and succulents are in it. Filler Use whatever you want as a filler. Empty or water-filled soda bottles work well. A properly made gritty mix holds no (or VERY little) perched water, so there is no worry about water perching above material used as a filler. Squirrels The gritty mix won't deter them. I probably found 30 black walnuts buried in the pots of material I'm growing on for bonsai that I've repotted so far this spring. You'll need to find an alternate method of dissuading them. Gran-I-Grit is actually mined by the NC Granite Corp in Mount Airy, so it shouldn't be too hard to find there. If Manna Pro is all granite and the right size, there's no reason it can't be substituted for Gran-I-Grit. The mix is 1:1:1 by volume, then a tbsp of gypsum/gallon of mix. The bark I use is pre-screened, but if I had fines, I would use them in the 5:1:1 mix, spread them on the garden or beds, add them to the compost pile, or use them in hypertufa projects. I always use either insect screen over the drain holes or plastic canvas, which is an inexpensive plastic mesh that comes in 9x12 sheets, available at most hobby stores in the needlepoint section. Paste this to your browser to see what I'm talking about: http://bagntell.files.wordpress.com/2009/12/pcanvas2.jpg Al

Topsoil is a poor choice as an ingredient for container soils. Maintaining a steady pH, or adjusting to a target pH is often a problem for greenhouse/nursery operations, and extremely difficult for hobby growers. I would advise you to skip the frustration and not even try to hit/maintain a target, choosing instead to learn how to help insure that media pH is estimated to be under 6.0 and use an acidifying fertilizer . Coir generally has a much higher pH than peat, so is probably not the best choice in a soil used for blueberries. You won't need to worry about bringing the plants indoors or offering any special cold protection in zone 9, either. Do a search of this forum using the words blueberries soil pH and you'll find enough good information to keep you occupied well into the night. 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.