I have not needed to do any side by side comparison because my mix is economical and effective. I hate soil with wetting agents. It makes it easier to over water (especially for seedlings with damping off) and when you’re watering thousands of potted plants you don’t have time to check each pot for its individual needs, you just have to water them in groups.
My mix is heavy, but that is one of its virtues. I’ve worked in nurseries where large numbers of plants blow over every time it’s windy. This often leads to damage. Very few of my potted plants fall over even in storms and a couple of plants which happen to be good at catching wind have blown off shelves and still tend to land upright since they’re not top heavy.
Also, the only nutrient I’ve needed to supplement is the nitrogen to get healthy plants. I don’t supplement the phosphorous or potassium because the compost seems to be pretty balanced aside from being low on nitrogen.
You are a pro and have worked out a system that works for you, but I guarantee you that many weekend type gardeners would over water starting seedlings in your mix. I don’t agree that wetting agent lends itself to over watering in a high quality peat-lite type mix. It should train quick enough to serve the needs of establishing seedlings if you are watering daily. I think amateurs tend to drown their starts more than anything else, but as a result of using heavy mixes.
I’m professional with fruit trees but merely an avid amateur starting vegies, although I’ve been doing it for over 50 years. I have never lost a plant to damping off that I can remember. I usually start plants in a southern window and accelerate growth by moving them into a gro-closet at night. My “greenhouse” is unheated but well ventilated so even when I start plants there, damping off has not been a problem.
I use a similar mix as you as far as using compost for greater water holding capacity- the compost performs pretty well as a wetting agent when mixed with peat, but after draining contains much more available water than peat. However, the mix I use for my trees won’t work so well for vegie starts.
Fine scotch is a good reason to use peat.
For reasons real
or imagined, some
look at anything
that might substitute for peat.
At current usage rates, peat is not going to run out.
And for some applications there are no substitutes nearly equal to peat.
I was only thinking about starting vegetable plants. I don’t use Pro-mix in my tree nursery’s pots, I make my own mix and use 1/3rd compost by volume and equal parts peat and perlite or sand. The sand is fine but perlite, of course, is lighter. These trees are started in special bags in the soil so most of what is in the pot is straight soil, but surrounded by a better draining mix. Somehow it works, but all I’m trying to do is keep the trees healthy by then- they are already sellable size. Most of the pots are 25 gallon- the bags are 18" diameter.
It seems peat is produced at a rate higher than it’s consumed…so I guess that is confirmation that it is ‘renewable’. (7.3 million tons of coal mined in Columbia shipped to Germany last year…now that’s an example of non-renewables being consumed—by a nation claiming to be ‘green’ no less).
Anyone using peat should feel proud they are utilizing a renewable resource that there is more of than when the first peat was harvested.
Unless I’m mistaken the rate of growth doesn’t apply to harvested areas because the surface has been stripped. The surface vegetation is what produces the new peat. I take no issue with peat harvest for local use, but think areas without natural peat resources should use local materials instead of shipping in peat. Same as I take no issue with coastal populations consuming salmon, but don’t think it should be supplied throughout the entire continent.
You’re right that there doesn’t seem to be a valid argument about peat not being renewable, but rather the harvest greatly impacts the ecosystems from which it is taken.
Doesn’t harvest of almost anything in the category of ‘natural resources’ have some local ecosystem impact? From Lithium mining or gold or copper mining, to logging operations…among them peat harvest seems to be less impactful in a negative manner than just about anything, be it Nitrogen fertilizer, Phosphate fertilizers, Potash mining, crude oil extraction for all the tons of plastics in all our homes, cars and everything else.
I concur there is some local pollution in peat extraction, as about any other kind of resource harvest.
And I also agree that buying/using local is good practice, if possible. Be it peat substitutes or locally grown produce. *But, peat substitutes that are often suggested, such as coir…do not meet the ‘local’ criteria any more than peat, and for many applications is a poor substitute.
Sustainability discussion aside; I find locally produced composted yard waste makes a superior base for potting mix compared to any peat based mixes I’ve ever used.
I have been using decomposed wood chips, blended with compost and biochar, with some good results. Wood chips are plentiful, I guess they may break down faster than peat and thus not be suitable for long term potting applications. But long term potting applications aren’t for me anyways.
If that was true, it seems to me that commercial green house growers wouldn’t spend the fortune they do on pro-mix formulas. For annuals, peat-lite can be hard to beat- I make my own mix for trees in big pots because I need the superior water retention of compost over peat. Trees grow great in a light mix if you keep it moist- but I don’t use drip and depend largely on rain and a hose. .
On the other hand, I have gotten outstanding starts on a certain type of mix that seems devoid of peat-
seemingly pressed without pots, why hasn’t the process been embraced by the industry?
Obviously, peat needs more nutritional supplementation than most composts, as a base, but composts don’t drain as well. Drainage is the most crucial element of pot production.
I ought to be using more peat and sand on trees and shrubby plants.
For, some get root rots in winter sitting outdoors.
But, peat or any other organic matter shrinks a lot…leaving a potted tree to ‘wobble’ in it’s planted hole if not staked…
something bare root trees don’t have to deal with.
Silty, sandy, topsoil is great.
For seeding annuals, the need for peat and perlite is hard to find a good substitute for.
Ashes can help for some things, but others don’t need the alkalinity.
Sand by itself sometimes can be ok for starting seedlings that are going to be bare-rooted
transplants.
Fine-ground bark is a poor substitute for peat in many applications.
An organization I’ve been a member of, presented at, and attended meetings for many years is hosting a free webinar on peat land reclamation. Link to American Society of Reclamation Science