Thanks for the great tip! I have not used vermiculite yet but I use perlite a lot to amend the soil I use for my plumeria cuttings, plumeria seedlings and my growing baby succulent collections.

I'm trying vermiculite for the first time this year for seed starting. My only complaint with it is that it's difficult to tell when it needs watering. But it's fine and lightweight and very nice for starting small seeds.

I am trying vermiculite in some of my pots to see if I can hold some moisture in the hot Texas summer...hopefully it will drain well.

Hetty: Thanks for this timely and very good tip! Spring is arriving in most areas of North America (at least I hope everyone is finally warming up!) and what a great time for this tip to appear ... when folks are thinking about sowing and planting!

Years ago you could find vermiculite for sale in the garden department of all the big box stores but none of them in my area seem to carry it anymore so I purchase it at a local nursery who does stock it on occasion. I use straight moistened vermiculite as well as vermiculite combined with a little potting medium when I root cuttings, and as Dutchlady stated it works really well for starting seeds and seedlings! I've copied and pasted the following information from Wikipedia:

VERMICULITE:

Soilless growing media: exfoliated vermiculite is combined with other materials such as peat or composted pine bark compost to produce soilless growing media for the professional horticulturalist and for the home gardener. These mixes promote faster root growth and gives quick anchorage to young roots. The mixture helps retain air, plant food and moisture, releasing them as the plant requires them.

Seed germination: either used alone or mixed with soil or peat, vermiculite is used to germinate seeds. Very little watering is required. When vermiculite is used alone, seedlings should be fed with a weak fertilizer solution when the first true leaves appear. A tablespoon of soluble fertilizer per one imperial gallon (3.78 : 1) of water is the recommended mix.

Storing bulbs and root crops: pour vermiculite around bulbs placed in container. If clumps are dug, allow to dry for a few hours in the sun and then place in cartons or bushel baskets and cover with vermiculite. The absorptive power of vermiculite acts as a regulator that prevents mildew and moisture fluctuation during the storage period. It will not absorb moisture from the inside of stored tubers, but it does take up free water from the outside, preventing storage rot.

As a soil conditioner: Where the native soil is heavy or sticky, a gentle mixing of vermiculite up to one-half the volume of the soil is recommended. This creates air channels and allows the soil mix to breathe. Mixing vermiculite in flower and vegetable gardens or in potted plants will provide the necessary air to maintain vigorous plant growth. Where soils are sandy, mixing of vermiculite into the soil will allow the soil to hold water and air needed for growth.

PERLITE:

In horticulture, perlite can be used as a soil amendment, a medium for hydroponics or for starting cuttings. When used as an amendment it has high permeability / low water retention and helps prevent soil compaction.

Thanks for the reminder, Hetty. I'm going to be using it more for starting tiny seeds.

Thanks for posting that information, Lin! I hadn't thought about using it for storing bulbs; that will be much easier than the sand I'm using now! Not to mention MUCH lighter!

Woofie, you are very welcome ... yep, a lot lighter than sand or even wood chips for storing bulbs!

If you can find a source of vermiculite from home insulating companies, it should be cheaper than from nurseries. The vermiculite mines that had asbestos in them have been closed for decades.

http://www.dhs.wisconsin.gov/e...
"Vermiculite mined today for use in insulation is from a source considered to be free of asbestos contamination. "

If the "insulation vermiculite" is coarser than you want, just rub it between your palms and you can reduce it to grit, sand or powder very easily. You can screen it with 1/8" tulle or window screening in an embroidery hoop.

However, if you find cubic yards of vermiculite in your attic, don't go rooting around in it or re-use it in the garden. Old enough vermiculite CAN have asbestos mixed in.

Good ideas! I agree vermiculite for starting plants, perlite for making the medium lighter and more well drained. With coarse horticultural grade perlite you can make your own potting soil from equal parts of perlite, fine pine bark mulch and peat or coir.

Around here the nurseries last year were all supplied with fine non-horticultural grade perlite--a sticky useless white dust. So check that what you buy is coarse horticultural grade perlite.

When making potting soil mix for plants down here in Florida where there is nothing but sand which can compact to a very stringent degree: I like to use both vermiculite and perlite along with some potting soil & sand. I mix them all together. Generally, anything I'm putting in pots is only to grow them on until they can go in the garden. I find the perlite lightens the mixture considerably & the vermiculite holds more water so it doesn't run through the sand & perlite. With the extreme heat we have here I need something to hold the moisture in the soil & the vermiculite does that well.

>> I find the perlite lightens the mixture considerably & the vermiculite holds more water so it doesn't run through the sand & perlite. With the extreme heat we have here I need something to hold the moisture in the soil & the vermiculite does that well.

I agree that vermiculite holds water well. And vermiculite + Perlite provide more lightening and aeration than peat would.

If you buy a bag of bark mulch and screen out the biggest chunks and smallest powder, you might like replacing some or all of the Perlite in your soil mix with bark "grit" or small nuggets. Say, 1/16" and 1/8" and 3/16" ... up to to almost 1/4"

You can use bark nuggets a little larger than your Perlite as a 1-1 replacement for Perlite, because bark holds more water than Perlite for the same size granules.

Or, you could replace some of the vermiculite by using some finer bark (fibers and powder up to 1/16" as the water-holding ingredient. Any size vermiculite holds more water than bark, but very fine bark does hold a moderate amount of water (say, around half as much as an equal amount of peat moss).

Some fine bark + some gritty bark + some 1/8" + some 3/16" bark will keep the sandy mix "open" and aerated, but still hold some water.

And bark is cheaper than either Perlite or vermiculite, if you screen it yourself.

As always Rick --- you rock!

Rock - oh yes, "crushed rock" , that's good too! From grit up to very fine gravel. But heavy and expensive.

Actually, Thank you! Once I discovered pine bark, I went crazy for it, and even use fairly fine bark for seed starting.

But really SMALL seeds that need to be sown on the SURFACE need a smoother surface than that, so I put down a thin layer of vermiculite for them.

Vermiculite on the top for those really small seeds!!!!! Why didn't I EVER think of that!!????!!!!!??????

Excellent! You done good Rick.

You are too kind!

I lost a whole tray of petunia seeds (128 cells, over a dozen varieties). I should have realized that was going to happen when I dropped the TINY seeds into big crevices, like dropping a basketball down a flight of stairs.

My theory is that vermiculite is translucent, so even if a seed gets washed under one chunk of vermiculite , enough light will still reach it for germination.

I do believe your theory is correct. I recently did some rudbeckia seeds & unfortunately only 1 came up & I did make sure there were no crevices but what are crevices to our eyes in relation to crevices to itsy, bitsy, teeny weeny seeds?

Rudbeckia and daisies are two things I've never tried to start from seed.

I would wish for more room so I could try more things, but first I would have to wish for more time (like, retire!)

I suspect then I would have to wish for more energy. When I look at Himalayan Blackberry trying to choke out an azalea, I wonder about whether there were any way to weed laying down ... but then standing back up would seem like a lot of work.

Hmm, there is n o "lazy" emoticon. I guess "lazy" and "gardener" don't go very well together!