adding sand to potting soil?

New York, NY(Zone 7a)

I have some culinary herbs for pots. A rosemary that I've had for a year that may need to be transplanted to a larger pot, and two newly purchased small sage and thyme plants (maybe 8 oz cup size, I don't have the inch size handy) They all recommend soil that has the characteristics of sandy, dry, well drained, or lean. I don't want to make a potting mix completely from scratch, but...

-Should I add sand to common store bought potting soil to make a very basic custom mix?
-What type of sand (builders or coarse, not play sand)?
-What ratio of sand to potting soil?


Prairieville, LA(Zone 9a)

.A lean soil is one that doesn't have a lot of organic material in it like compost, peat moss, etc.

You want a soil that will drain fairly quickly and not hold a lot of water. Try putting the soil you have in a pot and water it thoroughly...see how long it takes for the water to drain from the pot....well drained soil will allow water to flow through it in just a minute or two depending on the size of the pot. If water sits in the soil, you can add 1 part coarse sand to 4 parts soil and see how that drains...make sure all the drainage holes in the pot do not get clogged with can use gravel or bits from broken pots to keep the soil from running out or blocking drainage.

Here is some info for you.

Russell, KY(Zone 6b)

I would add perlite rather than sand- it allows more air in where sand can compact over time.
It also goes a lot further and per cubic foot can even be cheaper.
A bonus is that the pots remain lightweight.

New York, NY(Zone 7a)

What about if I started with the 1 to 4, sand to potting soil ratio? But, made half sand and half perlite? Getting the best of air, and a little more bottom weight on some things, like a taller dwarf meyer lemon for example. Wind gusts knocking over pots is a pain. Using only perlite for the pots that benefit from being kept lighter etc.

New York, NY(Zone 7a)

Most all store bought potting soil drain well after a thorough watering? (like the test suggested 1-2 min.)


This message was edited Jun 26, 2011 12:08 PM

This message was edited Jun 26, 2011 12:10 PM

Russell, KY(Zone 6b)

Quote from physeek :
Most all store bought potting soil drain well after a thorough watering? (like the test suggested 1-2 min.)

It drains well but is still too dense IMO. Almost every bag of potting mix I have ever bought has been too heavy to suit me- I always add perlite or sometimes peat or vermiculite- depends on the plant. Once in a while I get hold of a bag I like but then forget to remember which brand it is for the next time.

Sand is fine, especially if you need the weight.
It's just somehow something I have never used much as an amendment.

Prairieville, LA(Zone 9a)

My Rosemary is in the ground and has been for a few years. I amended the clay soil with a 1 part sand 4 parts inexpensive potting soil and have had pretty good success. By the same token I have sages , basils and oreganos growing in containers filled with $2.50 the 2 cubic ft bag potting mix and they are all doing well also. It all really boils down to cost/budget. availability and how it is to be used. For most container plants good drainage is the issue and the herbs mentioned do not need nutrient/organic matter dense soil.

Below is the rosemary.

Thumbnail by themoonhowl
Ellendale, DE(Zone 7a)

I mix a little sand into almost everything I pot, especially cacti and succlents.

Tapla (Container Gardening Forum here on DG) says to go with sand that is half the size of a BB, no smaller. The principle is that fine sand takes up all the air spaces that you need for good drainage in your soil/pot.

Any coarse contractor or builder sand would suffice. Look at it through the package to see how coarse it is­; the coarser, the better!

You could also check around for very small aquarium stone sold in pet stores.

By the way, I mix a little sand and fine gravel into Miracle-Gro orchid mix (in bags at Wal-Mart), and my plants seem to love it.

Ayrshire Scotland, United Kingdom

If you go to the garden center and walk around to the area where the gravel, bark etc, etc is in bags, normally there is small bags of HORTICULTURAL sand, this is sand that has no lime etc added, I, like some of the other people who answered you, add this sand to lots of plants that are growing in pots and their requirements are for well drained soil, because herbs don't like wet soil, heavy pots wont be an issue as the sand helps to drain the water away, I also add some fine grit to things like Cacti along with sand/ compost, if your herbs wilt a bit in summer pots, then sink the pots into a bucket of water for an hour to really wet the compost, remove the pot from the bucket, let it drain and hey presto, your herbs will be away again as good as new. My mixture for potting herbs, Lavenders and Cacti, I use 4 parts compost- one part sand, add one part fine gravel also to this mix for Cacti,
Never use builders sand as there are all sorts of stuff in this from cat's pee to eggs from insects, the sand I use is for horticultural use, is sterilized and costs pennies for a small bag. you don't need a large amount to pot up several pots of herbs.
Good luck. Weenel.

Ellendale, DE(Zone 7a)

Good ideas. I never thought much about the purities/impurities of the sand in bags. I know that Lowe's and other home centers sell a "washed sand" for sandboxes (for children) that I would assume is cleaner. However, if you use fine sand, it goes against the drainage that you're after.

New York, NY(Zone 7a)

I only locally see "play sand" - that's too fine as suggested, "quickcrete multi purpose sand" -states may contain silicates, and I can't see inside the paper style bag. I don't see horticulural sand anywhere . I"m not sure I can find the right coarse sand.

I did see a small 8 qt bag of miracle grow perlite. Also the local stores have .5 cu ft. bags of mini marble chips, or bags of pea gravel.

-The mini marble chips and pea gravel look small, are these small enough (very small aquarium stone was suggested)?
-Marble better than pea gravel?
-Was thinking of trying 4 parts potting soil to1 part drainage aid combo mix (the drainage combo mix would be equal parts mini marble chips or pea gravel and perlite)?

Any suggestions, or should I keep looking for the right sand or get small aquarium stone etc.?

Thanks for everyone's ideas thus far.

Russell, KY(Zone 6b)

You could always go to a feed store and get chick grit- it's certainly an economical way to go and will not influence pH.

Prairieville, LA(Zone 9a)

Physeek...perlite will work just fine. It will do the same as the sand/gravel/marble chips. Just add one part perlite to 4 parts soil if ya need to improve drainage. If the soil drains well, water flows out of the holes within a minute of two, you won't really need an amendment. It is easy to get caught up in all the varying methods/.amendments. The major consideration is fast draining soil for herbs. Many potting soils already have sand as an ingedient as well as perlite.

Ellendale, DE(Zone 7a)

Yes, I agree with themoonhowl. Sometimes we get caught up in doing it just right. I would experiment with what's available and with what you have on hand. I have a bag of pea gravel that I occasionally remember about, lol ... to toss a few stones in my mix.

No worries.

Ayrshire Scotland, United Kingdom

The best thing to do is, Test and try, there is very few things that are set in stone for gardens especially when you think that we all have different types of soil, temp, long / short seasons, so when you get replies, these are usually guidelines, I am a visitor to USA every year and believe me, the DIY ?garden stores all sell horticultural sand in very small bags, small grit will also do, perlite too, all great for drainage and there are just as many things gardeners use for water retention, so my advice would be to take all the replies that are offered and try a few out, there will be at least one that will suit your needs, thats what gardening is all about, handing down tips, advice and do / dont's.
Good luck to all the gardeners, enjoy, thats the best part of gardening.

Casper, WY(Zone 4a)

I have used Miracle-Gro for years before they started to add too much bark in their mix. I also had trouble with weeds in it and once in a while fungus gnats. Now I use EXPERT which is much finer. Walmart sell it.

During the 80's. I owned and operated a commercial greenhouse when I lived in Nebraska. I used a commercial mix which I made from scratch. It was 1 part each of peatmoss, perlite, and granulated plant food according to direction. Plants grew great in it and it was lightweight. I used the same mix for cuttings. For succulents and cactus, I added sand to make it leaner.

Edited for spelling

This message was edited Jul 13, 2011 10:51 PM

Ellendale, DE(Zone 7a)

Good idea; I want to try the Expert brand. I have noticed that the Miracle-Gro mix does dry out fast, probably due to all the bark.

I think it's great to bounce ideas off one another. That's what these forums are intended to do. Thanks for all the ideas.

Wellborn, FL

Please tell me how deep a pot I need for my thyme plant.

Prairieville, LA(Zone 9a)

Standard 8 to 10 inch pot...6 to 8 inches deep should want to have at least 2-3 inches of soil below the root ball.

Shawnee Mission, KS(Zone 6a)

We use potting mix for all our herbs in pots. I add compost to the mix when growing veggies in pots. We have thyme and rosemary both in raised beds and in containers. I also add a slow release fertilizer to the containers. The herbs are doing well in both areas. We do make sure that they get reduced watering and full sun.

We have clay soil here and the recommendation from the extension office is not to add sand to the soil. Their thing is that clay, sand and heat makes brick. I'm not sure that I agree with that exactly but we have quit using sand and moved to all compost as a soil admendment.

Port Townsend, WA

I am filling large containers for planting1) a manzanita, & 2) a mix of herbs. These are smaller (galv. metal) cattle troughs with holes in the bottom. I have a layer of 3/4 washed gravel in the bottom plus a layer of clean local sandy soil. Now I am adding potting soil & my current plan is to mix in sand, but what sand? The garden center sell tiny 2lb bags. The hardware store offers "play" sand or "sharp" sand in opaque bags ... Perlite may be great for plants, but surely a poor choice environmentally (mined, heated, shipped a long way, etc.) & a bit pricey & peat moss use is worse.
I think I want the sharp sand? Any suggestions?

Hi PT Artist. I recommend you walk down to the beach with a small bucket and collect natural sand. I live on the Wenatchee River so I get course granite type sand. Any ocean sand would of course need to be thoroughly washed to remove salts. If you have a fresh water source nearby, use that instead. Store bought sand is the same thing except they bake it to sterilize it.

Lake Stevens, WA(Zone 8a)

If you have not yet done this, I agree about the beach sand (but beaches there are often rocky). But if you still need to buy sand, you are correct, the "Sharp Sand" is the one you want.

Poughkeepsie, NY(Zone 6a)

I use perlite.

Magnolia, TX(Zone 8b)

It was my understanding that a bottom layer of rocks is being discouraged as a 'potting' practice? I am not talking abt broken shards over drainholes as being a layer...anyone have an update on this and the why?

South Florida, FL(Zone 10b)

I don't know about cold climates, but here in South Florida you have to be very careful with adding sand. Sand down here usually harbors the dreaded root knot nematode. I know a few people who brought them into their gardens when adding unsanitized store bought sand. They are a huge problem down here, but I don't think they are up there.

Post a Reply to this Thread

Please or sign up to post.