If you want to omit perlite for drainage. Can you substitute small pine bark and pine fines in the mix?
EDIT: Question is for potted soil mix.
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Here in NW Vista CA, no.
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I myself have never heard of anyone using perlite in garden soil, unless you are talking about raised beds.
Actually a lot of people use pine bark in their garden soil and that can work great if you use the right amount, which I have no idea how much.
We don’t use bark or perlite in our actual garden, I do in grow bags. Lots at the top, that stops the soil from drying out as fast. It also keeps squirrels from digging in our grow bags. Squirrels love to dig in any loose dirt that they find.
Although when I use grow bags we buy bagged soil, and sometimes that bagged soil contains bark in it.
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I know some have substituted rice hulls for drainage
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I have been using that in pots, and I am stilling using perlite in pots. The problem with rice hulls, is that they are not as cheap as getting bark mulch by the truck load, unless someone lives in a rice growing region.
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I have used it in soils of such heavy clay that you could throw pots with it. I was partially inspired to use it because of the frequent claim in the literature that using sand would turn the clay into concrete. That claim was intended for farmers who would need to convert acres of clay soil into a better draining one in order to grow crops, but ended up also being directed to homeowners. I’ve since learned that 8 to 12 cubic feet of sand can be mixed with a clay soil to create mounds in heavy soil where fruit trees can thrive that would otherwise struggle. Sands a lot cheaper than perlite but both are difficult to mix with clay.
I use perlite in the potting mix for the 25 gallon pots I use in my fruit tree nursery to stop the pots from being excessively heavy.
Incidentally, that warning about the use of sand is another example of poor communication through cooperative extension, something I have been devoting some attention to lately. The difficulty of converting excessively clay soil to useful agricultural land in large scale is much different than serving the needs of a small home orchard. It requires a whole lot less sand.
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I meant soil for pots.
Yes, that is what I heard and scared me from using sand in pots so went with $ perlite. I’m about out of perlite and didn’t want to buy another big bag of it I don’t need for just a few more potted figs.
It is too $$ if you buy in small bags. I buy a big 4CF bag for $32.
For potted figs I was going to try pine fines, peat, mini pine nuggets as the pot mix and leave out the perlite.
I’m using different fertilizers every month. I start with fertilizer pellets, then Miracle Gro, then fish emulsion, then a last dose of Miracle Gro. When I make the mix, I also add a couple of tablespoons of AG Lime per 5 gallons of pot mix. I was also thinking about trying pee, but seem to be doing good with what I got. A lady that moved gave me some old Miracle Gro, fish emulsion and Orchard fertilizer and I have enough for a few years.
Some of the mail order figs I bought from One Green World had sand in the pot mix. They didn’t use bark. Looked like soil/compost, peat, sand and maybe some fines. But that was a while back and I may be wrong.
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I’ve gone to using homemade biochar/charcoal in my potting mixes, and I’ve been happy with that. Works well for lightening and opening the soil, yet it also holds moisture.
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Pine bark fines are nice if you mix them with something. On their own they are too acidic==maybe fine for blueberries.
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if i could find pine bark fines, id use them. im in logging country yet cant find a source for them. i have to drive 3.5hrs south to lowes or home depot to get any. the lowes up here only carries the colored mulch and online lists the bark fines and nuggets perpetually out of stock. so i still use perlite.
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ill be upping my game with bio char. i just pulverize bulk charcoal into 1/2 pieces then steeped in a little molasses, fertilizer and compost. im using a 3in. 4ft alder log in a 5 gal bucket to break it up but its alot of work. any ideas on how to easily break up charcoal? a wood chipper would be ideal but i dont have one.
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For small veg and other annual starts the perlite is probably worth it, but for trees, sometimes you actually want a heavier mix so they are lest prone to blowing over when the mix starts to dry out.
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I’ve been experimenting with several ways of crushing. For mixing into larger beds, I just pound on it with a short wooden post, and I don’t worry much about consistency or getting it very small. For potting mix I set up a 2nd hand sink and garbage disposal. I just run a hose into the sink at low flow, plug in the disposal and start adding charcoal to the sink. I have to push it in to the disposal some with a stick. It drains out into 5 gallon buckets with drain holes.
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@alan, do you have a recipe you use for larger trees?
We are pretty close to Canada so peat moss isn’t too expensive. By volume I usually use equal parts compost, perlite or sand and peat moss. In my 25 gallon pots I often use perlite because I’m transplanting trees I sized up in 18" in-ground bags in real soil that I put into the pots separating the soil from the edge of the pot with potting mix. If I use sand the pots get very heavy.
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I prefer vermiculite over perlite because it doesn’t migrate to the top of the pots as much.
Last year I used a 50/50 mix of peat and perlite, but that retained too much water. My blueberries, hazels, and chestnuts suffered in it. This year I’m using a 1:1:1 combination of peat:soil conditioner (pine fines):vermiculite. So far that formula has to be watered more often than the one from last year, but the plants seem to be doing well in it.
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Perlite is typically used in heavy peat mixes. For smaller pots and greenhouse type crops. It provides some porosity in these water holding mixes. Peat is a very fine particle. Perlite helps open it up some. Peat mixes are good where you have a tight control of the water, as in greenhouses or water isn’t abundant.
Pine bark mixes will drain a lot better than peat mixes, thus needing watered more often and have better porosity due to the larger particle sizes. You can’t turn off the rain, so drainage matters then the most. Or when employees over water in a shotgun watering scenario.
We used an 85% pine fines/mulch as the base of our mixes. The balance was a compost product for mycorrhiza properties and rice hulls. The rice hulls functioned like pine but was cheaper and we only used to soften the cost of pine fines. When I retired pine was $32 a yard and rice hulls was around $16 a yard. Just economics. We usually bought around 400+ semi loads a year of pine bark so it would make an impact. We already used the rice hulls to top off the pots around 1” thick to help prevent weeds. It did an excellent job. We had machines that applied it as the plants came off the potting lines.
We used this mix for potting just about everything grown outside and was watered by overhead irrigation or drip. It was forgiving of over watering.
For my personal needs I would be comfortable in 100% pine if I could supply the nutrients and water. I would amend my personal mix with peat, and compost as I hand water.
We added 8-9 month slow release fertilizer, Micromax for micros. Occasionally we used Epsom salts or aluminum products for blue hydrangeas. We didn’t add lime because our water had a lot of carbonates in it. It supplied the Calcium the plants needed for us, but may need to be added for calcium depending on your water quality.
The pH isn’t as critical in a soiless mix like ground mineral soils as you are supplying all the nutrients the plant needs, or should be, and the nutrients aren’t bound up like they are in mineral soils by high or low pH. I supposed if you had a heavy mix it may have more of a effect.
Gravel and sand doesn’t increase porosity and drainage. It can actually create problems by filling in the air spaces. It’s only used as ballast. Our mix was heavy enough, so we didn’t add any. By using a similar particle size you create gaps and space as the soil won’t mix together as tight. You put in multiple size particles they blend together tighter filling up those spaces in pine bark. They mesh together.
These were principles were laid out by Carl Whitcomb in his book “Plant production in containers” years ago in the 80’s and we tweaked them to meet our needs here in the Great lakes region.
The soil you choose will be determined by your watering practices and availability of water in your area. Nutrients are supplied by your choice of products organic or non organic. Lots of options.
As far as perlite in a pine mix, save your money.
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For starting seeds in a flat of smaller cells i will use perlite and peat based mixes. When I pot up to the next size I use pine bark in place of perlite.
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You don’t even need to mix it. Just make a berm on top. The roots will reach down to the clay during droughts, but the crowns will be well drained by the clay. Got the idea from a xeric / rock gardening book, but have been using it in general purpose beds for some years with great success. If some gets mixed incidentally while digging around in it or transplanting, no harm done.
To the topic at hand: I hate perlite. I use it very specifically for starting finicky seeds under controlled conditions, but otherwise avoid it. I’ve heard good things about turface as a potting medium, but haven’t found a local source to try it. I don’t tend to have things in pots long-term anyway, which obviates the problem.