Make Your Own Potting Mixes

March 29, 2011

Credit: Doreen G. Howard
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Container gardens are on my mind, as the winter chill is easing. I like to grow a few pots of various vegetables and flowers before the usual frost-free date here, May 15, to get a jump on summer.

I learned long ago that it’s much cheaper to make my own potting mix and store it in an old trash can, rather than paying for big sacks of potting mix. I can customize the mix for various plants, too.

The lighter the better when it comes to potting mix. Loose and porous mixtures not only make a container lighter to move, but they transport water, fertilizer and air to plant roots quickly.

It only takes about 20 quarts of custom-blended potting mix for this smashing window box.  It's on the acid side, with extra peat moss to provide more moisture for the begonias and callas. Credit: Doreen G. Howard

The perfect growing mix does not contain soil or garden dirt. It’s composed of peat moss, vermiculite or perlite, sand, and shredded bark or compost. Plants such as lettuce and many flowers like Russian sage and marigolds want sweet soil with a pH of about 7.5. Some are acid lovers, like ferns, asters and strawberries. They need a pH of about 5.5 to 6.0. Start with the basic recipe below and then add soil sulfur to lower the pH or lime to raise the pH. Both additives are sold in 4-pound bags and are found at garden centers.

If rapid drainage is needed, as in the case of cacti, succulents and lavender, add extra sand. For ferns and woodland flowers like primrose that require very moist conditions, include more extra peat moss for water retention.

Potting mix is easy to make and stores well in a sealed container. Credit: Doreen G. Howard

Basic Container Mix

1 bucket (2-1/2 gallons) peat moss
1 bucket(2-1/2 gallons) vermiculite or perlite
A half bucket (1-1/4 gallons) screened compost or composted cow manure
2 cups fine sand
2 cups pelleted time-release fertilizer
1/2 cup lime (to counter the acid of peat and keep the pH level near neutral)

Mix thoroughly. Makes enough to fill two 14-inch tubs or five 12-inch hanging baskets. Double or triple recipe for bigger containers.

How Much Mix Do You Need

Potting mix is sold by volume (measured in quarts), and most pots are measured by their diameter. To translate quarts of mix into various pot sizes, use this quick reference.

Container Size & Amount Needed

Pots & Tubs
8-inch        3 quarts
10-inch      6 quarts
12-inch      8 quarts
14-inch      12 quarts
16-inch      20 quarts
20-inch      24 quarts
24-inch      28 quarts
30-inch      72 quarts
36-inch      96 quarts

Hanging Baskets
12-inch       6 quarts
16-inch      10 quarts

Window Boxes
24-inches by 6-inches      12 quarts
36-inches by 6-inches      20 quarts

Next week, I’ll cover the right fertilizers for containers and tips for success.

So ask me questions you want answered in the comments below.

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Doreen Howard has written for The Old Farmer's Almanac All-Seasons Garden Guide for 15 years and is the former garden editor at Woman’s Day as well as a photographer. She has grown more than 300 varieties of heirloom edibles and flowers in the last two decades.

In stores now!

Look for Doreen's newest book, Heirloom Flavor: Yesterday's Best-Tasting Vegetables, Fruits and Herbs for Today's Cook. Find in stores everywhere including Walmart and on the Web including amazon.com.

Comments

I don't know very much about

By Hui

I don't know very much about gardening. I just bought some organic gardening mix. I am wondering, can I use it directly for planting tomatoes in a pot? Do I have to mix it with native soil or anything else? I don't have good soil at all at home...Thanks in advance for your help

I start and transplant about

By Dennis Early

I start and transplant about 400 veg and flowers from seeds. I use Bordines potting mix and use 6 bags at 3 cu ft each. $22 and change is getting expensive. Can I mix my own for this volume and cheaper? Also is the compost you buy in bags safe for seeds? Thank You, Dennis

Bagged compost is weed-free,

By Doreen G. Howard

Bagged compost is weed-free, from my 20 years experience of using it.  Price the materials to make your own potting mix to see if it's cheaper to make your own.  Prices vary so much by region, I'd hate to say it's cheaper.

I am using a wooden box

By jddred

I am using a wooden box approximately 24" x 120" for a garden of fruits and vegetable. Would this type of mix work or what would you recommend?

For raised gardens, layer top

By Doreen G. Howard

For raised gardens, layer top soil, composted cow manure, peat moss and a double layer of compost.  At the start of every season, add more compost.

Is it absolutely necessary to

By Maria Espravnik

Is it absolutely necessary to use manure / screen compost. Can it b garden soil, cheap potting mix…/and I add to it

I want to make my own potting

By Robert.copley

I want to make my own potting soil to save money. So where can I get the raw components for the best price?

I don't know where you live,

By Doreen G. Howard

I don't know where you live, so it's difficult to cite a specific retailer.  Generally, big boxes like Menard's and Home Depot have very competitive prices.

Last year for my balcony

By Mama Yah

Last year for my balcony container garden, I was advised to use Baccto Professional Planting mix. It worked fine for my lettuces, but for my pineapple tomato plant, carrots, and strawberries, it was a disaster. Would this mix you posted be better for fruit/root veggies, or is there something I could add to the Baccto I still have from last year. I haven't grown food in about 30 years. Thank you.

I'm not sure if this is the

By Hildita

I'm not sure if this is the right post to ask this question...I have a pot of calla lily and the leaves are getting yellow...do you think is because of to much water?...have them in the dinning not outside I see the leave sweating lot of water don't know what to do...any help will be really appreciated.Thank you very much

There are two reasons for

By Doreen G. Howard

There are two reasons for yellow leaves on callas: too wet soil and not enough light. Let soil dry out between waterings indoors and move the pot to an East or West facing window.

I just bought a pamdree mix

By Pong

I just bought a pamdree mix from Millers LLC in Hyrum Utah (you can google them they supply garden centers all over the intermountain west) and they did several tests to get a better pH and balanced nutrients in a clean and organic mix. I haven't planted anything yet (it snowed yesterday) but it's nice and fluffy and if you live nearby their plant you can pick it up in bulk. It cost me $80 for 1 cubic yard and was more than enough for my 10 3 foot 10 inch deep bed. They even scrubbed the bucket clean before scooping it and placing it in our truck. Does that sound like an okay price? This is the first time I've done square foot gardening although I've got two row gardens out back (we have high winds and need the harder soil for the plants that could blow away otherwise). I like that it was easy. I'll keep you posted if it grows anything.

Prices vary from region to

By Doreen G. Howard

Prices vary from region to region. If you are happy with the mix and plants grow well, that's all that matters.

Hi there, i have some self

By Karen Hayes

Hi there, i have some self sown baby trees and srubs which i dug up out of the garden last Autumn and put into pots, Lilly Pillies, Camilias and Azaleas there all doing very well and are now about 5" tall. my question is should i pinch out some top new growth to encourage side shoots? (I am in Australia, so its spring now over here.)

Karen, don't pinch until you

By Doreen G. Howard

Karen, don't pinch until you plant in the ground. If you intend for them to be solely container plants, repot to a larger container and pinch after you see new growth.

For succulents and other

By Doreen G. Howard

For succulents and other plants that need dry feet, add perlite. Half garden soil and half perlite. Then throw in about 25 percent finely shredded pine bark.

Hi Doreen,I recently

By Karen Hay

Hi Doreen,I recently purchased a bulk amount of garden soil from a local landscape suppply outlet.They told me that it does contain some peat and would be suitable to use as potting mix however i find it stays very wet to use for my succulents, what would you recommend i add to it to help it to dry out quicker?

Inside winter gardening

By ladykkb

I have had vegtable gardens off and on for many years. With the rising costs in the market, I am wondering if there are any vegtables that can be grown indoors through the winter months in a window with lots of sun, in a cold climate? Thinking of tomatoes and peppers..but how would they be pollinated???? Just curious and trying to eat healthy and affordably.

 It would be possible to grow

By Almanac Staff

 It would be possible to grow small vegetables like cherry tomatoes, lettuce, and herbs inside during the winter months, but with anything bigger, like squash, it would be difficult. Unfortunately, there isn't a lot of sunlight during winter, so you would have to have grow lights--lights that produce light sufficient for plants to grow on and produce a little heat. You can pollinate plants yourself too--just take a cotton swab and transfer pollen between the male and female plants. 

question

By tlgarza1

im trying to start a garden, its says this mix is for containers, would it work with vegetables. i have mostly peppers and tomatoes. currently using miracle grow mix but i want something cheaper.

Lasagna Gardening

By nanobitz

Because I couldn't go down with a garden, I've built layers in containers and on the ground using the Lasagna method. We've had extreme temperature fluctuations this Spring but I don't know if that is the cause of my stunted tomatoes and peppers. Should I start over? The average temp is in the 90's now. Thanks for your advice.

I prefer 1/3 sand, 1/3

By organicguy46240

I prefer 1/3 sand, 1/3 compost 1/3 spagham peat moss

I'm pretty new to gardening,

By peggy4110

I'm pretty new to gardening, with sand do you use coarse sand or fine sand or both. I was thinking for my summer plants (I live in Australia) a potting mix of peat moss, vermiculite, shredded pine bark, and either a coarse or find sand?
Thanks,

How much...

By Peaches57

If I have a container measuring 6' X 2' X 1/2' (Length X width X height to get area...how do you convert that to quarts?

It would be about 15.5qts for

By PepperGuy

It would be about 15.5qts for 6cu ft - a gallon and a half is just ridiculous.

Re: How much

By Doreen G. Howard

Multiply 6 by 2 by .5, which is 6.  That's how many quarts you need.

Garden uses

By rebekahnikole

Can I use this mix for my garden soil (in the ground?) Or is it best for potted plants? I have raspberry, rose bushes, veggies and herbs that do fairly well every year but I know they can yield a lot more then what I'v been getting.

Re: Garden uses

By Doreen G. Howard

This recipe won't work in the garden.  You can augment your soil with compost or manure, peat (if you need more acid) and shredded leaves.  Simply layer the materials over the existing ground and mulch with the leaves or finely shredded bark.  All are organic and will break down into nutrients during the growing season.  BTW, roses love peat, as they flourish in a slightly acid soil.  So do raspberries, blueberries and strawberries.  Also spread your coffee grounds around them.  Some rose experts suggest burying banana peels at the base of rose bushes to supply magnesium.

Confused!!!

By Jennifer Spielvogel

OK, I've read the comments about the Basic Mix recipe, and my page shows that the 2-1/2 gallons of peat moss is in the recipe. Is there something else missing? I am really confused here!

Re: Confused!!!

By Doreen G. Howard

Nothing is missing, Jennifer.  I left out the peat in the initial posting of the blog.  We corrected that error after readers brought it to our attention.  The recipe, as written above, is correct.  Sorry for the confusion.

My apologies

By Doreen G. Howard

As a number of readers noticed, I left out the first ingredient in the potting mix recipe.  Please add this to the mix: 1 bucket (2-1/2 gallons) peat moss.  My apologies for not proof-reading the post thoroughly.

Bad recipe!

By Laura D Snyder

This recipe is definately missing something, I would NOT use this as is!!!

Basic Container Mix Recipe

By marmulk

I have a question. As I was reading through this article, the recipe for the basic container mix said to add a 1/2 c. lime to counter the acid of peat to keep the PH near neutral. Peat is not listed in the recipe. Did it just get deleted or am I missing something?

shamrock plant

By maydaybby@yahoo.com

I always kill my shamrock plant and would like to know what I can use on it to keep it full and alive besides typical watering and sunlight.

Re: shamrock plant

By Doreen G. Howard

Shamrocks (oxalis) are bulbs.  The foliage dying naturally is part of the cycle after blooming.  Let the plant die, the container dry out and then dig up the little bulbs.  Store them in dry peat moss in a dark area.  Plant bulbs about 2 inches deep in pots at the end of August or in September.  Water well and place in a sunny window.  Bulbs will sprout and the cycle will begin again.

question

By Ann Wagner

this is a neat column. i hope this isn't a dumb question but does the basic container mix have the peat moss in it? i don't see it listed and was confused. thanks for your help.

Re: Question

By Doreen G. Howard

Ann, you are absolutely right.  I make an error and didn't list the first ingredient, which is one bucket (2-1/2 gallons) peat moss.  I didn't proof-read thoroughly.  Sorry!

Thanks

By Ann Wagner

No problem, thanks, Doreen, for responding to me!

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