Which potting soil to use?
- Thread starter ktrain
- Start date
ktrain
Moderator
Custom mixes are nice if you can afford all the stuff I've seen used.
But once you get up there and have to fill 100 to 200 pots, you have to get creative.
I still simply use 1 bag of soil conditioner to 1/2 bag of vigoro potting mix, add some #4 perlite and my mineral mix.
The trees seem to like it and it's a little easier on the pocket book.
I change out the soil every two years.
Figgerlickinggood
Well-known member
@BucksCountyFigs is this the thread you were looking for?
BucksCountyFigs
Well-known member
YES!! Thanks so much!
Figgerlickinggood
Well-known member
You are most kindly welcome.
Not a direct answer to your question, as I've changed my mix as many times as there are plants in my hard. But here is a summary of what I think are the key pointers for making your own potting soil, as well as an attempt at one-size-fits-all.
Short Answer: A DIY mix of 1/3 peat, 1/3 pumice, and 1/3 sand and perlite should work great. The more sand, the heavier and more structured; the less sand, the lighter but more prone to degrade, since perlite eventually grinds down into dust.
Long Answer: Depending on how much you want to water the plants and how heavy you want the containers to be, make a mix that is anywhere from 65 to 80% aeration/structure and the remaining 20 to 35% water retention. I would recommend not mixing anything organic into the mix other than peat moss and/or rice hulls. Although fig trees tolerate low oxygen levels and sludge around the roots better than most plants, you're playing with fire adding organics unless you're root pruning and repotting yearly. Compost and wood products will decompose, sap oxygen, and rot.
The aeration/structure elements you can choose from are:
-Pumice (lightweight)
-Perlite (lightweight)
-Sand (not lightweight)
-Decomposed granite (not lightweight)
-dirt from the yard, provided it's not heavy clay (not lightweight) and under the assumption it's probably full of weed seeds you don't want
-gravel/rocks (not lightweight)
The water-retention elements you can choose from are:
-peat moss (lightweight)
-vermiculite (lightweight, but can get gummy if you use too much of it)
-clay pellets (not lightweight, and expensive)
-calcined clay/oil absorber (not lightweight)
Wildcards are:
-rice hulls (people swear by these, and they're lightweight, but I'm not sure if they provide absorption or aeration or both, and can be hard to find)
-charcoal (it's organic, but won't break down; it's lightweight; and it will grab minerals from fertilizer just like a carbon filter does in the Brita pitcher; but it's expensive)
FigLab
Well-known member
Last edited:
TorontoJoe
Administrator
FWIW... You know I like SM#4 and Promix HP... But in a pinch I've used some good quality triple-mix that came in bulk from my local family garden centre. I add maybe 20-25% perlite. It performs every bit as well as anything that I've used... at least for the plant.... When it came time to move the pots there was some choice Italian cursing. So much heavier... if this isn't a concern for you then maybe something to consider. For the triple-mix.... it's like $50-$60 a yard/metre. That's hard to beat. Maybe for pots on wheels...
Do you happen to know what’s in Triple Mix?
TorontoJoe
Administrator
It can vary a bit depending on region but around here it's equal parts topsoil, peat moss and compost (manure).
I suppose if you want to be really cheap you can use sharp sand instead of perlite... but up goes the weight again.
BucksCountyFigs
Well-known member
The big bag (I think about 1.6cu ft) bag of the organic stuff has just been stocked at Costco.
grasshopper
Well-known member
Fig trees are tolerant of a wide range of potting mix.
I have been using AscPete's 4-2-1 (peat-pine bark fines - calcined clay) (58%-28%-14%) or variations for years from SoCal, to NJ to TX, in SIPs and in regular pots, mostly 5 gal buckets. Good pine bark fines are not easy to find.
In warm areas, and for small pots like a 5 gal bucket, they need to be amended every 2-3 years. You can get away with longer period if growing in cooler areas.
If you need a lot of soil mix(more than a few bags), it is probably a good idea to look into bulk mix available locally. Local mix formula and delivery options are something to consider unless you have a pickup. e.g. Some place charge per mile, some have a nominal charge within a radius, some requires min. yard like 3 of one product. And you can find out the recipe they use to decide whether it works for you. Try to stay away from those with a high percentage of compost. Compost is cheap and it breaks down quickly, usually in a season. So, a 40% compost mix can lose 40% of its volume in 1 season.
I have been using AscPete's 4-2-1 (peat-pine bark fines - calcined clay) (58%-28%-14%) or variations for years from SoCal, to NJ to TX, in SIPs and in regular pots, mostly 5 gal buckets. Good pine bark fines are not easy to find.
In warm areas, and for small pots like a 5 gal bucket, they need to be amended every 2-3 years. You can get away with longer period if growing in cooler areas.
If you need a lot of soil mix(more than a few bags), it is probably a good idea to look into bulk mix available locally. Local mix formula and delivery options are something to consider unless you have a pickup. e.g. Some place charge per mile, some have a nominal charge within a radius, some requires min. yard like 3 of one product. And you can find out the recipe they use to decide whether it works for you. Try to stay away from those with a high percentage of compost. Compost is cheap and it breaks down quickly, usually in a season. So, a 40% compost mix can lose 40% of its volume in 1 season.
TorontoJoe
Administrator
Oh.... same triple mix... I fill 5 gal pots with it (no perlite) and mass-root dozens/hundreds of Chicago Hardy and other common varieties outdoors in summer. I give them back to the nursery (where I get the mix) as small trees for them to sell. They're really nice people and run a little family business..... and they're kind.
My point being, that I root truck loads of cuttings with minimal effort behind my shed in nothing more than wet triple mix with a 75%+ success ratio. Maybe not the best way to root your S33... but it's good soil.
My point being, that I root truck loads of cuttings with minimal effort behind my shed in nothing more than wet triple mix with a 75%+ success ratio. Maybe not the best way to root your S33... but it's good soil.
Figjake
Well-known member
I can’t find pine bark fines for cheap so unless I find a way to mulch down a large quantities of pine bark mulch to a more fine product, it’s going to be 50/50 promix bx and compost from the local facility for me. The compost has a lot of wood chips in it that are going to take forever to break down. I also use a variation of Ascpetes amendments regimen for the soil mix. I mix gypsum, ironite, osmocote, epsoma, de, epsom salt into every soil batch. The amendments can get on the expensive side really quick when you have an army of pots and uppoting to do like I do this year.
I will also do jacks 20-20-20, fish fertilizer, cal-mag, silica gold every 2 weeks or so, or I did last year. It may not be every 2 weeks this year with a new baby
and basically doubling the number of pots I have. Probably time for an inline fertilizer.
I will also do jacks 20-20-20, fish fertilizer, cal-mag, silica gold every 2 weeks or so, or I did last year. It may not be every 2 weeks this year with a new baby
and basically doubling the number of pots I have. Probably time for an inline fertilizer.In my gardening experience (not figs, yet) is that custom mixes are way cheaper as volume increases.
1 cu yard of 50/50 compost/topsoil from your local landscaping company is usually only $30-$40 and it goes a LONG way. Just need to add perlite and coco coir/peat (both of which are also cheaper in bulk) and your favorite fertilizer mixes and you're off to the races.
I haven't done a full per cu ft cost analysis breakdown but I would find it hard to believe it is more expensive than a cu ft of pre-made mix from the big box stores.
Also if I need to make a smaller amount of mix (because a cubic yard is a LOT) i just do the same ratio using the 1 cubic foot bags of Timberline topsoil and 1 cu ft bags of black kow composed manure and follow the same recipe as above with your coir/peat and fert.
Based on feedback and other posts ive read on this forum I plan to just use the same mix I use in my pepper pots as the ones I will make for figs this year.
Kompakfigs
Well-known member
I believe his intent was to eliminate the use of perlite. Did you sift the mulch as noted in AscPete’s thread. I usually add compost to the 4-2-1 mix for more water retention but this year any rooted cuttings will go in that 4-2-1 without compost mix because I want them to grow as tall as possible.
superdave336
Well-known member
I agree and get my compost mix by the yard from landscape company. I then mix with other ingredients. The extra I store in totes and have ready when needed. I can't afford to buy decent soil by the bag for everything.
Dont think most of us can at scale haha talking about 10x the cost
grasshopper
Well-known member
AscPete's 4-2-1 mix is based on another mix(he mentioned it in his original post) which is well draining. I sifted the mulch at the beginning but it was too much work for all the pots so I tested it out and figured there was no need to sift them especially for the good ones that already came mostly in the right size.
I am not sure compost hold more water than peat but it does hold water. I usually try to keep compost to below 20% or it would be too much work to amend the soil each year.
Last edited: