Where to get horticultural grit?

[katkatkat]

With my asparagus plants in the post to me, I need to prep my bed for them tomorrow. Having read a few "how to plant" guides it seems I will need to improve the drainage and the best way to do this seems to be with as much horticultural grit as I can afford.

I've searched online on B&Q, Wickes and Screwfix (my three nearby DIY places) and none of them seem to sell it, only decrative gravel. Can anyone suggest somewhere with a physical shop that may have it? I've tried searching both grit and gravel and nothing comes up.

If I can't get it, would a few inches of pea shingle in the bottom of the trench do the same job?

Thanks!

[4390evans]

I know that dobbies do Alpine grit for £3.99 a bag, its a decent size bag depending on what you need it for. It also does the RHS bags of grit but they are tiny and at the same price.

It is hard to find, we have load of customers saying they had searched for it too.

[4390evans]

[bario1]

Hi Katkatkat, you can buy it at H*mebase at Blackhall, but I warn you it's about £6 a bag! I didn't add any to my bed, I just dug in tons of leaves - not the same i know, but they were free...

[fishpond]

If you have a local garden centre, try them.
Mine were £4.99/bag for the same use as yourself.
If the soil is anything like heavy they will not survive-----at least mine didn't 10 years ago.
Trying again, only properly this time.

[Muddy_Boots]

I would say that unless you want to spend an arm and a leg to do what it says in some circles I wouldn't get horticultural grit. Its only called 'horticultural' because its been graded extra so its all the same size and is still the same as normal building type grit/gravel only smaller.

When I put my Asparagus in three years ago I dug the soil out of the area I was planting it in and mixed 1 spade of builders sand and 3-4 spades of used compost from old growbags and chucked in a couple of handfuls of growmore in a wheelbarrow, mixed thoroughly and then put it into a pile to put back. I then created the ridges on the two rows for the crowns, placed the crowns evenly along both rows then used the same mix to cover the crowns with. Never had any trouble with drainage and the plants have grown with no problems. This year is the first year of proper harvesting.

[bario1]

I thoroughly dug over the whole area, then incorporated a barrow of rotten leaves per square metre, then added five or six bags of farmyard manure and dug that in a bit. Then i dug out the trenches, created a ridge in the bottom from quality mpc, put the crowns on the ridge and backfilled. Finally, I dug a deep drainage trench around the whole bed and filled that with gravel, so effectively, it's a raised bed. They grew well last year, I'm just keeping my fingers crossed that they reappear this year, cos it was a lot of faff for nothing if they don't!

[katkatkat]

Thanks for the advice and suggestions. I think our subsoil is heavy clay (given the pond they started to dig on site filled up almost to the top without a liner in it) so a little concerned about the drainage issue. Hadn't considered building a moat

[mothhawk]

I acquire all my grit in the summer.. For free. When the roads are being sprayed with tarmac and re-gritted, if you look along the verges carefully, you can nearly always find a spot where the grit spreading machine has been refilled, leaving a decent pile of granite grit in the grass, or sometimes if you are exceptionally lucky, in a neat heap in the gutter. Get your bucket and spade out and shovel it up. Last year I found a huge pile - filled 4 (5 gallon) buckets and still some left over.

[katkatkat]

I acquire all my grit in the summer.. For free. When the roads are being sprayed with tarmac and re-gritted, if you look along the verges carefully, you can nearly always find a spot where the grit spreading machine has been refilled, leaving a decent pile of granite grit in the grass, or sometimes if you are exceptionally lucky, in a neat heap in the gutter. Get your bucket and spade out and shovel it up. Last year I found a huge pile - filled 4 (5 gallon) buckets and still some left over.

They don't really do that sort of thing in the city centre sadly.

[vixylix]

I used pea gravel in the bottom of my raised bed - at the time BQ had it on offer for £1 a bag - but even normally its quite reasonable.

I suppose it depends how much you're looking for - if you need a lot you can find tonne bags for about £40 if you shop around?

No idea on the horticultural grit I'm afraid, but if its just for aerating the soil, gravel is gravel!

[katkatkat]

In the end I dug down as deep as I could (which apparently is one spade depth before you hit impenetrable ground that the tines of a fork will only go a cm or two in to). Couldn't get grit so put a layer of pea gravel in the bottom (not sure if it will actually help) and then built the ridges with manure and compost before back filling with compost and soil.

I guess only time will tell if it was the right thing to do.

[flynch]

I've used washed children's play sand, no problems. Very cheap from home base too

[WalterWhite]

Pea gravel as mentioned in-thread is a good option i have done that myself or if your looking for a more fine aggregate then try granite dust. Not so dissimilar to the volcanic dust 'hyped up fad' and considerably cheaper.

To make a significant difference to the soil condition you may need a lot aggregate plus as much organic matter you can throw in too.

Good luck.

RHS advice : Adding grit, sand or gravel to clay soils:
Clay particles are amazingly dominant in a soil. This is explained by the relative size of the different particles (clay, sand and silt) that soil contains. Clay particles are very small but, because this allows more particles to fit in any given space (say 1cm cubed), they have huge surface area that dominates the physical properties of soil. In comparison, sand and silt particles are larger, so fewer particles are needed to fill a space (say 1cm cubed again). As a result, the overall surface area of sand and silt is smaller and so much less influential on determining the characteristics of a soil than the clay particles.

In practice what this means is: to dilute the proportion of clay in a heavy soil requires very large volumes of grit or other material. It is seldom feasible to do this on anything but a small scale and, for most gardeners, other options such as raised beds, adding organic matter and choosing plants that thrive in clays are more practical.

Even where a clay soil contains for example 40 percent clay particles (a relatively modest content compared to heavy clay soils), the proportion of clay in the top cultivated part of the soil would have to be reduced by half to make the soil easy to work. This would require 250kg per sq m (460lbs per sq yd) of grit or gravel. Adding materials to clay can also make the clay less stable, so the soil becomes harder to manage. Experimenting on a small scale at first is recommended to be sure that any additions are worthwhile and won't have damaging effects on workability of the soil.

[B]
Granite Dust;

[It never rains..it pours]

I washed b&q sharp sand through a kitchen sieve. It was a shock how much fine went through sieve, about 33%, which when it settled went solid so can see why fine sand and clay are a bad idea. End result appeared good stuff, no fines and no traces of salt. I only did 2 bags though, may not be good idea if a lot to do