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Apr 25, 2018 11:29 PM CST
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While on my adventures of plant shopping, I happened across someone seemingly knowledgeable when it came to potting mixes. She was listing off general consensuses I had found online about the DIY mixtures. I have all tropical plants, except for a few (I have about 23 plants). The one I'm most concerned about is my Mimosa Pudica which has grown exceptionally well the last winter (indoors), with just a 1:1 typical potting mix + perlite. When I up-sized it's container, I read online it's good to incorporate sand into the mixture. While speaking with this worker, they recommended the sand from within sand bags of a vehicle (for weighing it down in winter [Canada]) as the coarse sand options. I hesitated but she highly suggested it. She listed off all kinds of names of plants, mixtures, etc, seemed to know what she was talking about!

I went ahead and used that in any DIY mixes of potting mix for my plants. I wasn't overly concerned about it but now my Mimosa is progressively getting works from the bottom going up. Slowly turning yellow and leaves falling off. Nothing else has changed other than the mix going from 1:1 standard mix:perlite to now 1:1:1 standard mix:perlite:coarse sand. Is there fungi/bacteria/things to worry about within that sand? Also my Moses in a Cradle / Boat is withering away too. Everything else using those mixes are doing fine. The Mimosa Pudica I've had growing since last summer, the Moses in a Cradle / Boat is new so I'm still grasping how to properly maintain it. Also worth mentioning my other Mimosa Pudica (same soil mix) is doing fine.

TLDR: Is sand within a vehicle weigh down sand bag for winter driving safe for potted indoor plants?

Last edited by MimosaMan Apr 26, 2018 12:35 AM Icon for preview
Apr 26, 2018 5:17 AM CST
Name: Will Creed
Prof. plant consultant & educator
I spent many years researching various potting mixes and fertilizers. The varying recipes and theories behind each are mind-boggling. Everyone seems to have their own recipe for success and is convinced it is the right one for everyone. After 35 years working professionally, here is what I have learned:

1. Repotting is often unnecessary and a common cause of plant failure, regardless of the potting mix. Think twice before you repot and use any potting mix.

2. A good potting mix has to allow for some water retention, but be porous enough to allow oxygen in around the roots. Many different potting mixes can provide this.

3. Perlite is a better ingredient for adding porosity to the potting mix than sand or vermiculite. Even coarse sand particles are too small to provide good porosity. Its now used by professional only in situations where added weight is important. Vermiculite tends to compact too quickly

4. If you want to avoid pest and diseases problems for your indoor plants, then use a potting mix that contains only peat moss, coir, and perlite. Other organic materials may harbor gnat larvae. Never use outdoor garden soil for indoor plants.

5. Fertilizer is vastly over-rated because indoor potted plants use nutrients in surprisingly minute quantities. Brand names are meaningless. Complete fertilizers that contain trace and minor elements are what you should look for.

6. The potting mix that works best for you is dependent on your watering skills.
Will Creed
Horticultural Help, NYC
Contact me directly at [email protected]
I now have a book available on indoor plant care
Apr 26, 2018 10:53 AM CST
Name: Daisy I
Reno, Nv (Zone 6b)
Not all who wander are lost
Garden Sages Plant Identifier
I agree With every bit of what WillC has said.
Life is not a journey to the grave with the intention of arriving safely in a pretty and well preserved body, but rather to skid in broadside, thoroughly used up, totally worn out, and proclaiming...."WOW What a Ride!!" -Mark Frost

President: Orchid Society of Northern Nevada
Apr 27, 2018 9:08 AM CST
Name: Will Creed
Prof. plant consultant & educator
I should have added that some plants, including most succulents, require a more porous potting mix than most other indoor potted plants.
Will Creed
Horticultural Help, NYC
Contact me directly at [email protected]
I now have a book available on indoor plant care
Apr 27, 2018 11:39 AM CST
Name: Philip Becker
Fresno California (Zone 8a)
I suspect the sand was contaminated. I'd change it out ASAP.
I use washed sand, gravel, or regular aquarium gravel, in my soil mix.

IMPORTANT ::: DO NOT USE PLAYGROUND SAND !!! There is something in playground sand that will kill plants. I suspect, something they treat it with so weeds don't grow in it. Scarry, HUH !

Good luck, my friend. 👍👍
Anything i say, could be misrepresented, or wrong.
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