Purpose/advantages/disadvantages of container ingredients

tam91 · April 5, 2011

I personally don't use the self-watering containers, I just grow my tomatoes in 18 gallon tubs. In the past, I've used a mix that worked for me, but isn't generally considered very good I believe (1/3 composted horse manure, 1/3 peat, 1/3 topsoil). I was thinking of modifying my mix some this year. I probably will not be buying the soil-less potting mixes, that's just too expensive for me. So I was wondering, that purpose the various ingredients have, and the advantages and disadvantages of each.

So here's my guesses and some questions - please correct me where I'm wrong.

Topsoil - nutrients for plants. Disadvantage - compacts. Inexpensive

Composted manure - same as topsoil. Additional disadvantage - weeds.

Mushroom compost - same as topsoil, even more nutrient-rich

Peat - nutrients. Holds water. Compacts?

Bark fines - aeration. Does this use up nitrogen though?

Vermiculite - aeration. Kind of expensive

Other ingredients - ?????

ireilly · April 5, 2011

Perlite. Adds air space and drainage, relatively inert and a natural product. You can get a 4 cu ft bag for around $20 from a hydroponics store, may be larger amounts available.

fortyonenorth · April 5, 2011

Topsoil - nutrients for plants. Disadvantage - compacts. Inexpensive
heavy, generally does not drain well in a container

Composted manure - same as topsoil. Additional disadvantage - weeds.
yes, same disadvantages as topsoil. However, I've put an inch or two of composted manure on the very top of the potting mix (once it's settled) and it provides a good source of nutrients over time.

Mushroom compost - same as topsoil, even more nutrient-rich
mushroom compost is derived from the mushroom growing medium which is generally peat with added straw and lime. It is lighter than topsoil, is relatively inexpensive if purchased in bulk, but can be high PH, so be careful how much you add.

Peat - nutrients. Holds water. Compacts?
good water retention and a valuable ingredient of most mixes. No nutrient value and generally low pH.

Bark fines - aeration. Does this use up nitrogen though?
excellent ingredient that generally makes up at least 1/3 - 1/2 of my mixes. No nutrient value, good aeration. Pine bark fines will not tie-up nitrogen, but be careful of what you purchase, because I've seen bags of "fines" which actually include a fair proportion of shredded hardwood, which will tie-up N.

Vermiculite - aeration. Kind of expensive
perlite serves the same purpose and will hold up longer than vermiculite. Not sure about comparative price, but I get a very big bag of perlite for about $15

Other ingredients - ?????
Turface, Pros Choice and other calcined clay products, most often marketed for ball field conditioners, are excellent additions to potting mix. I get Pros Choice from a nearby John Deere Landscapes retailer, but I'm not certain of their distribution.

matilda'skid · April 5, 2011

If that worked for you use it. Top soil in a container doesn't drain for me and did not work. I tried compost in a big stock tank that also didn't work. I use potting mix in my pots because it drains well and plant roots reach to the bottom. If I tried your mixture it would be soggy here.

platys · April 5, 2011

I used top soil my first year out of ignorance. I had a good haul of tomatoes, but it did compact as the season went on, and was slow to drain. I'd have to water, let it settle, water some more, let it settle, etc.

tam91 · April 5, 2011

Thanks so much everyone.

I must have some sort of dumb luck, because it drained fine for me. Dunno.

I thought mushrooms were grown in composted manure - apparently that's incorrect?

I'm talking about 32 containers, why I'm being "cheap" and not just getting a mix (also not too enthused about things purchased in bags)

The local place sells a bulk mix of topsoil, mushroom compost, and sand - that's intended for the garden itself though, not containers. I was considering that however, plus adding some peat and bark fines though, if I can find them.

Or just doing the topsoil and mushroom compost (I can get both in bulk) and adding peat and fines.

I realize it's not considered ideal - but hopefully doesn't sound like a disaster?

fortyonenorth · April 5, 2011

The mix that I've used with good luck is peat, pine bark fines and perlite. My basic mix for each of my containers (2' X 4' X 18") is:

6 cu. ft. pine bark fines (i.e. 3 bags)
10 gal perlite
10 gal peat

lime
3 c. balanced organic fertilizer
1 c. greensand for micronutrients

tam91 · April 5, 2011

Interesting, so that's WAY more aerated than my mix. I need to find stuff I can buy in bulk, I'll have to run down the road one of these days and see what's available.

If I don't have problems with drainage, which I don't, how do I know if the mix I'm using is causing any problems? I can see it's probably not the best aeration - but what difference would more aeration make?

fortyonenorth · April 5, 2011

Tam - when I first sought information on how best to compose a container mix, I found this thread on Gardenweb: http://forums2.gardenweb.com/forums/...615891.html?70

Tapla (Al) is a Master Gardener and his thoughts on container gardening are very instructional. I think you'll find it useful. I don't frequent GW very often, but I keep a printed copy of this thread in my garden journal so I can refer back to it periodically.

tam91 · April 5, 2011

Thanks, I'll go have a read.

matilda'skid · April 5, 2011

I buy mushroom compost from Miami Oklahoma. It has chicken manure in it and what looks like grass or hay. I have rotten straw bales around and what is in the mc is not stemy like straw. I use it for a mulch because it doesn't have weed seeds. I wouldn't even try it in a pot except a little on top, but I would put it in a raised bed. The materials you are using would work in a raised bed. How I would know if it wasn't working is the plants would die. If they live and you get tomatoes you did well.

b54red · April 5, 2011

Matilda, it sounds like you have a source for the good mushroom compost. The stuff in the bags is useless because it packs too much and has little organic structure left in it. I used to have a source for the mushroom compost made with straw and chicken manure and gypsum. I used it alone in some pots and grew tomatoes in it and they did better than any of the soil less mixes I have tried since then. It stays rather loose and drains well while feeding the plants good. If you have some why don't you try just filling a large container up with the mushroom compost and plant one tomato plant in it and see how it does. I think you will be pleasantly surprised.

matilda'skid · April 6, 2011

It smells like it would be super fertile when it is "fresh" but I will try it. I actually plant most of my tomatoes in the ground. I have lots of plants in pots because of trees in my yard so I buy too much potting mix. I have made some with perlite, peat and pine bark fines also.

Lunacy · April 10, 2011

Quote:

Originally Posted by fortyonenorth

Tam - when I first sought information on how best to compose a container mix, I found this thread on Gardenweb: http://forums2.gardenweb.com/forums/...615891.html?70

Tapla (Al) is a Master Gardener and his thoughts on container gardening are very instructional. I think you'll find it useful. I don't frequent GW very often, but I keep a printed copy of this thread in my garden journal so I can refer back to it periodically.

Wow! I learned a great deal, reading that! Thank you forty for sharing. I am just a second year gardener, but I feel I have made enough mistakes to have been doing this wrong for ten years!

dice · April 12, 2011

"Topsoil" has a lot of variability in how much native gravel
is in it. That could account for differences in drainage.

This document has a lot of useful information on what
makes a good container mix:
http://edis.ifas.ufl.edu/cn004

April 5, 2011	#1
tam91 Tomatovillian™ Join Date: Aug 2010 Location: Crystal Lake IL Posts: 2,484	Purpose/advantages/disadvantages of container ingredients I personally don't use the self-watering containers, I just grow my tomatoes in 18 gallon tubs. In the past, I've used a mix that worked for me, but isn't generally considered very good I believe (1/3 composted horse manure, 1/3 peat, 1/3 topsoil). I was thinking of modifying my mix some this year. I probably will not be buying the soil-less potting mixes, that's just too expensive for me. So I was wondering, that purpose the various ingredients have, and the advantages and disadvantages of each. So here's my guesses and some questions - please correct me where I'm wrong. Topsoil - nutrients for plants. Disadvantage - compacts. Inexpensive Composted manure - same as topsoil. Additional disadvantage - weeds. Mushroom compost - same as topsoil, even more nutrient-rich Peat - nutrients. Holds water. Compacts? Bark fines - aeration. Does this use up nitrogen though? Vermiculite - aeration. Kind of expensive Other ingredients - ?????

April 12, 2011	#15
dice Tomatovillian™ Join Date: Jan 2007 Location: PNW Posts: 4,743	"Topsoil" has a lot of variability in how much native gravel is in it. That could account for differences in drainage. This document has a lot of useful information on what makes a good container mix: http://edis.ifas.ufl.edu/cn004 __________________ -- alias

April 5, 2011	#2
ireilly Tomatovillian™ Join Date: May 2010 Location: Dallas Posts: 344	Perlite. Adds air space and drainage, relatively inert and a natural product. You can get a 4 cu ft bag for around $20 from a hydroponics store, may be larger amounts available.

April 5, 2011	#3
fortyonenorth Tomatovillian™ Join Date: Jan 2010 Location: NW Indiana Posts: 1,150	Topsoil - nutrients for plants. Disadvantage - compacts. Inexpensive heavy, generally does not drain well in a container Composted manure - same as topsoil. Additional disadvantage - weeds. yes, same disadvantages as topsoil. However, I've put an inch or two of composted manure on the very top of the potting mix (once it's settled) and it provides a good source of nutrients over time. Mushroom compost - same as topsoil, even more nutrient-rich mushroom compost is derived from the mushroom growing medium which is generally peat with added straw and lime. It is lighter than topsoil, is relatively inexpensive if purchased in bulk, but can be high PH, so be careful how much you add. Peat - nutrients. Holds water. Compacts? good water retention and a valuable ingredient of most mixes. No nutrient value and generally low pH. Bark fines - aeration. Does this use up nitrogen though? excellent ingredient that generally makes up at least 1/3 - 1/2 of my mixes. No nutrient value, good aeration. Pine bark fines will not tie-up nitrogen, but be careful of what you purchase, because I've seen bags of "fines" which actually include a fair proportion of shredded hardwood, which will tie-up N. Vermiculite - aeration. Kind of expensive perlite serves the same purpose and will hold up longer than vermiculite. Not sure about comparative price, but I get a very big bag of perlite for about $15 Other ingredients - ????? Turface, Pros Choice and other calcined clay products, most often marketed for ball field conditioners, are excellent additions to potting mix. I get Pros Choice from a nearby John Deere Landscapes retailer, but I'm not certain of their distribution.

April 5, 2011	#4
matilda'skid Tomatovillian™ Join Date: Feb 2010 Location: Missouri Posts: 309	If that worked for you use it. Top soil in a container doesn't drain for me and did not work. I tried compost in a big stock tank that also didn't work. I use potting mix in my pots because it drains well and plant roots reach to the bottom. If I tried your mixture it would be soggy here.

April 5, 2011	#5
platys Tomatovillian™ Join Date: May 2010 Location: Naperville, IL Posts: 176	I used top soil my first year out of ignorance. I had a good haul of tomatoes, but it did compact as the season went on, and was slow to drain. I'd have to water, let it settle, water some more, let it settle, etc.

April 5, 2011	#12
b54red Tomatovillian™ Join Date: Sep 2009 Location: Alabama Posts: 7,068	Matilda, it sounds like you have a source for the good mushroom compost. The stuff in the bags is useless because it packs too much and has little organic structure left in it. I used to have a source for the mushroom compost made with straw and chicken manure and gypsum. I used it alone in some pots and grew tomatoes in it and they did better than any of the soil less mixes I have tried since then. It stays rather loose and drains well while feeding the plants good. If you have some why don't you try just filling a large container up with the mushroom compost and plant one tomato plant in it and see how it does. I think you will be pleasantly surprised.

April 6, 2011	#13
matilda'skid Tomatovillian™ Join Date: Feb 2010 Location: Missouri Posts: 309	It smells like it would be super fertile when it is "fresh" but I will try it. I actually plant most of my tomatoes in the ground. I have lots of plants in pots because of trees in my yard so I buy too much potting mix. I have made some with perlite, peat and pine bark fines also.