I would like to grow blueberries commercially in pots and outdoors without tunnels (in Turkey). For about a couple of weeks I am trying to gather information about an ideal composition of growing media. (with regard to both yield and cost).
Here are what I have found:
%45 perlite,%45 peat moss %10 pine bark as mulch (according to a peat moss supplier and blueberry grower in Turkey)
%30 coco husk, %70 coco peat, particle size 8-12mm and 2-8mm respectively. (according to a coco peat supplier in Australia),
%70 coco husk, %30 coco peat (according to a coco peat supplier in Europe)
%40 untreated, raw peat moss, %40 coir (shredded coconut husk) % 20 perlite. And a handful of soil sulfur. (according to Colorado State University)
The formula of Colorado State University is also supported by a master thesis I studied.
What are your suggestions? did you have any bad experience with regard to a constituent?
Has anyone tried pumice instead of perlite?
What about the lifespan? Which one would need replacement or addition sooner?
Additionally, some claim coir has better air filled porosity…
Those sound too expensive to me. I believe in much of the southeastern USA blueberries are grown in raised beds of sawdust or composted sawdust. The sawdust would be much cheaper if you are in an area with lumber mills. Or look for anything organic. Some other type of organic material that’s cheap.
Your mixes sound good for pots. But that sounds like an expensive way to grow blueberries. I grew blueberries in pots for about 10 yrs. It’s an awful lot of work and expense for what little you get. I remember up to 10 lbs per pot but it was usually less, sometimes way less and that was in a greenhouse.
I agree with fruitnut on the difficulty of container culture. It can be done although raised beds are the way to go. I have both. I use root pouches, and they are not moved, so I can supply 30 gallons of soil in each. The blueberries grow fairly well, like mini-raised beds. I also have raised beds.
I myself prefer to grow in mostly pine bark. I use the same mix for both containers and raised beds. 3 parts pine bark, 2 parts raw peat moss, and 1/3 part diatomaceous earth the size of perlite. I myself do not want perlite, drains too quickly. If I didn’t have pine bark I would use perlite to give aeration to the soil. The pine bark does that for me. The DE helps retain water in the soil. DE holds 120% of it’s weight in water. Undamaged perlite holds 0%.
DE will hold air when empty so can supply to roots also.
You mention pumice, it is not as good, but would be a good substitute for DE. I think pumice holds 60 or 90% of it’s weight? I don’t remember off hand? I use it for cacti, as I use a mineral soil mix for them and it helps keep some moisture around the extremely small roots cacti have. I would use pumice over perlite if I was you. Oh Perlite is good for 5-10 years, pumice and DE should last decades or longer.
Soil should be replaced every 3 years, but you could go as long as 7 years as long as you feed them well. The soil will compact and perform worse each year after 3 years. I replace mine after 4 years.
Maybe, but it has a higher pH. I do not like this product. Nothing works as well as peat.
Pure mixes of coco would need to be amended with sulfur. It’s tough to get pH right but with pine and peat which have a pH of 5.0 you’re there already, you just have to maintain.
I mulch with pine needles, oak and maple leaves or pure pine bark depending on what I have on hand.
If your water is higher than neutral you could raise pH while watering. I use rain water only.
The pH of water can be adjusted with sulfuric acid.
Actual topsoil, mixed with pine fines and peat moss, of hardwood mulch if you add some nitrogen, have worked just fine for me. Lack of water at critical points in summer will be a bigger problem than choice of media.
Pine bark may be better than sawdust. Whatever you can get cheap that would make nice raised beds. Maybe mixed it in some with the soil. I think some raised beds for blueberries are straight organic material.
I would like to thank you all for sharing your insights and experiences.
I further read a couple of papers and think that you can create a blend which would work, according to your budget as long as peat is the main ingredient and you pay attention to the drainage and aeration by means of DE or perlite and pine bark.
Andrew, special thanks for information about diatomaceous earth, perlite and pumice.
Here, interestingly, the cheapest one is perlite.
In one research study they used %50 peat, %25 perlite and %25 sand with remarkable results.
Now I am going to search a bit for sand options… May be I can reduce the overall cost a bit more
Sand is a fine amendment. With blueberries it remains neutral which is nice. Yes anything can be used with a skilled grower. I don’t have budget concerns since I only have 9 blueberry plants. I prefer a mix I only need to monitor pH once a year. Sometimes the more plants you kill the better grower you are! I killed some with a high pH, but once I fixed that I killed a couple with too low a pH! Well I learned well. I hate when you lose a plant and you don’t know why. Hard to learn anything that way! So I try to figure it out.
One note on sand for horticultural use, you want sharp sand. Like builder’s sand, you do not want beach sand, it has rounded edges and tends to clump. Sharp sand only.
We use beach sand here and I’ve never had an issue with it clumping- at least I think of it as beach sand- comes from Long Island. Maybe I’m misinformed on the nature of the sand I use, but I’ve never heard the shape of sand discussed in literature on the subject. I’ve used the stuff from LI in pots in my nursery and to amend excessively clay soil (which the literature falsely claims always creates concrete) and the results have consistently been good after 25 years of frequent use. In clay soil, I think the literature assumes you will use an inadequate amount of sand to overcome the liabilities of clay. You have to use as much as 50% sand to improve clay soil.
At any rate, I suggest you at least experiment with the cheapest salt-free sand available and find out how it works. The results should be immediate.
Peat moss rapidly breaks down into straight humus, losing some of its benefit as an aerating amendment and evaluating its expense should include factoring that in.
Here is a nice article about adding sand to clay. The only mention of sand types to use is to use rough “builders” sand and not smooth playground sand. I purchase my sand form a masons yard so it must be builder’s sand but on a couple of occasions I’ve used bags of playground sand with no ill affect.
Playground sand is rounded, and water rounds sand off just like playground sand. Ever see a piece of glass in the water? How the edges are worn smooth. It begins to look like a rock.
The same thing happens to the sand. It becomes very rounded.
Play sand should be non-toxic, non-staining and containing sub-rounded grains.
Just like beach sand. The clumping I speak of is only noticeable from the elevated perched water table it creates. What I meant by clumping it forms a continuous section that increase surface tension, thus defeating gravity and elevating the perched water table. Sharp sand has much less surface tension. So basically the advice is to use sharp sand like Builder’s sand. Beach sand certainly is not sharp sand.
What Not to Use
Although sand may seem similar in size and weight, there are sands that shouldn’t be used in the garden due to their makeup. Beach sand has silicon dioxide or quartz. It is rocky and doesn’t provide the space that plants need to find oxygen and water in the amended soil as easily as plain coarse sand from the garden center. https://www.hunker.com/12263411/type-of-sand-for-a-vegetable-garden
i agree. the cheapest organic material is most practical for acidifying. Sawdust is practically pure sugar(albeit hard-to-digest cellulose),and anything that is eaten(in this case, by microbes) will have acidic byproducts. Admittedly sounds gross, but as outright proof --our poop, pee, and even exhaled gases have acidic properties.
just as milk or steamed rice turns sour when microbes take over, cellulose will have the same fate when metabolized by microbes/fungi, acidifying the soil it is in
Sorry but it’s common knowledge not to use beach sand. It surprises me you do not know this. Yes read your link and I have no issue, agree completely with it, it does not say to use beach sand. It doesn’t mention beach sand at all. Do I really need to prove everything I say? One cannot give advice without backing links? It’s up to the person seeking the advice to decide if valuable. This is not an academic site.
I feel the same about David Pavlis. But agree he is correct.
Kim-Carlisle who is the source worked at Wellspring Gardens for 40 years.
Bet you can’t find one source that says to use beach sand, so could you prove it please? Back your statements like you want me to back mine. I provided 2 links that back my statement, so far you have provided zero to back yours. The link you provided does not endorse beach sand. States to use sharp sand which backs me 100%. As my comment was use sharp sand and your source 100% agrees with me. So I guess the argument is is beach sand sharp. And obviously it is not. If anybody wishes to ignore my advice feel free. This conversation is pointless I’m done with this pointless and incorrect criticism. Do whatever you feel correct, I really do not care.
We had a big problem with rotten sawdust when we first started with Blueberries in the field. The PH was too high. I was told later that hardwoods normally produce a higher PH than pine.
We now use something called “soil conditioner” which is a commercial product made from different sizes of ground pine bark. We plant blueberries in 1 gal and 3 gal pots using 100% soil conditioner which works great but the containers have to be watered just about every day. We use the same material as a mulch on the field grown blueberries. Its about $20/yard delivered
I will agree that the internet has many sources that refer to using “sharp” sand and that there may be a researched basis for this recommendation, however I just can’t come up with it. Extension sources simply seem to emphasize using courser sand and don’t use the term “sharp” or round.
Most recommendations about avoiding beach sand seem to be about salt but some are about the shape of the particles.
What I do know is that beach sand drains freely and sandy soils near the beach, previously under water, seem to have the exact qualities of sandy soils everywhere I work sandy soil. Plenty of sand not from the beach used to be beach sand.
I’ve encountered many horticultural myths in my lifetime that are passed on with certitude. I’d like for this forum to be a place that potential myths are challenged without it being taken as a personal attack.
And in horticulture as well as many other realms, "common knowledge’ contains a lot of often repeated myths. Carl Whitcomb made a career of debunking such myths through his horticultural research.
I love it when members supply their own observations, even if they are only anecdotal and possibly mistaken, but passing along other people’s anecdotes- not so much. Members have a right and reason to pass on their own experiences- it is one of the most rewarding things that happen on this forum.
In my life I’ve passed on many mistaken assumptions because the evidence seemed conclusive to me. At least when I relate them, I can include the fact that they are based on anecdote only. What “seems” to be true often is coincidental and based on unseen factors.