What Is Sharp Sand Gardening

intel Gardener

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Was looking to make my own seedling compost and I read somewhere to use 50% Horticultural sand and 50% sieved compost, but sharp sand is much cheaper and looks the same.
Would it be ok to use this, only I guess that the horticultural stuff is washed more and better graded? but if it does the same job for 1/2 the cost
HarryS Eternally Optimistic Gardener

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Hi Intel , The Horticultural sand Vs Sharp sand question comes up often on here . I think the majority of use Sharp sand , horticultural sand is so very expensive ! I mix it 1/3 sharp sand to 2/3 compost.
I asked the same question in a garden centre many years ago and was told that horticultural sand is less likely to have 'salts' in it.
Perhaps this is true, but then when you look at the spec for River / sharp sand it usually refers to it as "Washed sand" so by my estimations, it should be virtually free of salt.

I now purchase "washed" sand from a builders merchant.

I think what is more of an issue is the site the sand was quarried from i.e. is it from and inland quarry or the sea shore?

If I found it to be the latter then I would expect highish salt levels!

But considering I have been using it for 20+ years I will still use the builder merchant.

On the same theme; I buy kiln dried sand in lieu of garden centre silver sand and it fits the bill nicely!
As Tee Gee has pointed out, it's all dependant on where the sharp sand is from. Horticultural sand is more or less guaranteed to be free of lime and salt. But the sharp sand is so much cheaper that it's worth the extra effort of giving it a wash in a bucket of water first.
Good tip re. kiln dried sand!
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As for the salts point, I remember this from my school days. Salt is water soluble, so can easily be washed out.
I've used ordinary sharp sand many times without problems, but if I was worried about the salt, I'd give it a good wash first. Maybe put it in a big bucket, fill with water, swill it around loads and loads then leave it to stand for an hour or so, swill it again, then when the sand settles to the bottom, carefully pour off the water. Of course that wont be practical with anything more than tiny quantities (such as you might use top pots of compost to reduce moss and algae), and to be honest I wouldn't bother any way.
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I always buy 2 bags of sand from the Builders merchant in the Autumn open up the bag and leave propped up on the fence and let the winter rain do the rest.
I use this in all my mixes and have never had a problem , quick method as stated wash out before using under a slow tap other wise you will have nothing left

Spruce
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Sharp Sand it is then
What do you Guys think of the the 50 / 50 mix? or should l switch to
the 1/3 - 2/3 mix? - its mainly for seeds like Gerbera, Dianthus, Celosia
etc, going to start Dahlias as well (for cuttings) but was planning to half bury them just in normal compost to get them going....thanks for the replies
I use around 6 to 1 ( compost to sand)
- Like x 1
Things would probably grow in almost 100% sand but they'd get really hungry. I think I use up to one third sand or grit.
I make compost the same way I cook - a bit of this, a handful of that, depending on what I've got in the house.
pete Growing a bit of this and a bit of that....

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I just add sand to compost depending on what I'm growing.ie, how free draining I want it to be.
And I must admit to going by the look and feel once the sand is mixed in.
For certain plants I do buy grit, its expensive, but not sure if you can get a builders alternative which is cheaper.
On the subject of sharp sand containing salt, I doubt very much that builders would be very happy if it did.
I've never had a problem with sharp sand direct from a builders merchant
intel Gardener

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Thanks all for the replies, I made about a 3 to 1 mix (3 parts compost) and seeded about 8 trays today and I would think about the same again tomorrow.
So I guess it will be ok as provided they germinate quickly they wont be in the trays to long to worry about...........the hardest part is the sieving :(
What compost are you using? If its your own home-made compost you might want to sterilise it to kill the weed seeds.
If it is multi purpose compost, from a bag, then my solution is to buy John Innes Seed Compost. I only use one small bag a season as I reuse it for subsequent batches [not if any disease seen though], and I prefer the really fine, sandy, texture as I think it just "falls off the seedlings" when you prick out, therefore less chance of root damage.

Beware that reusing seed compost runs the risk that seeds from an earlier batch, which did not germinate, may germinate in a later batch.
intel Gardener

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It was normal (brought) multi purpose compost made by J Arthur, but it did have lots of bits of straw, which were sieved and the sharp sand added (3/1 ratio)Innes Seed compost is good but the cheapest I have found is £3 for 20lts but when you have 30 odd trays to fill, its still not cheap.
- Agree x 1
30 full sized trays is a lot of plants!
I buy the best quality - want to make sure that I get as many seeds to germinate as possible, and have decent drainage to reduce likelihood of damping off etc.

I use 1/4 sized trays, and have about 30 of those. I use them in rotation, plants are usually pricked out within a month and the tray, and its compost, are then reused. I keep the compost from year-to-year too - reserving fresh this-season compost for precious seeds, and last-years for things which germinate quickly and grow like weeds! like Tomatoes and the like.

Many of the things I grow only have 5 or 10 seeds in a packet, so I get anything up to 5 varieties in a single tray. The trick is knowing what to combine so that they will be ready for pricking out at the same time, and need the same temperature regime etc. but I expect you have the same issue with full sized trays, or you are growing a lot of plants of the same variety.