I live the U.S. but I read UK gardening books. Can someone please explain what is "Horticultural Grit". What is it make of, what is the size of the particles? Is there some standard reference that defines or specifies "Horticultural Grit"? If I wanted to buy it in the U.S., what would I ask for?

Thanks for the help.

  • In the US, I have hard clay soil, its hard work but if you turn the soil with Gypsum and compost, fresh soil, you will have well prepared garden bed for any plantings. Gypsum is the key... I have had great success with a nutrient depleted clay filled yard turned floral landscape. I noticed Monty Don uses grit alot and was here searching for more information. Thank you for your definition, use and where to buy. – Erin Sheffo May 25 '20 at 15:01

Horticultural grit is washed grit with a particle size of 1-4mm, or sometimes 2-6mm, with a neutral ph. It is intended for use in some potting mixes that you make up yourself, or to make a commercial potting mix more free draining (such as for alpines) or for adding to open soil, especially heavy clay soils, to open it up, improve drainage and aeration, and help break up the clay. Its usual to use the smaller particle size for potting soil,but either size is fine in open ground. I have absolutely no idea what an equivalent might be in the USA I'm afraid, since I'm in the UK. I guess any grit or gravel with an equivalent particle size that has been washed, or you wash thoroughly yourself to remove any lime or other elements (which should make it neutral ph) would do the same job. Certainly, many horticultural grits are actually gravel, just of a certain size and washed. We also have horticultural sand available, which is washed, graded, coarse sand - the nearest equivalent would be undyed play (as in children's sandpits) or silver sand, though the latter may be slightly less coarse than true horticultural sand.


Just search horticultural grit. Walmart has it, Amazon, or go to your local farm supply store and ask for poultry grit - probably your cheapest route. Or go to your local rock/stone center and ask for granite grit for your garden. It is nothing but very small angular shaped stones - not pea gravel although if that is crushed it would work. It is just crushed stone. In gardens it is used for drainage - how much depends on how sharp you need the drainage to be. Add it to lavender beds or alpine beds for drainage along with crushed oyster shell for calcium. If you have chickens or other poultry - you feed both free choice (separately). The grit (crushed stone) is used by the chicken in their gizzard to help digest their food. Without it, they will get food impacttion if fed anything but chick starter or laying crumbles. So if you have young poultry, once you start giving them grass, fruits, vegetables,bread, etc - then they need grit. If they feed free range eating all kinds of things from grasses to bugs to mice, etc, they need it too. Chickens that roam several acres over rocky gritty soil, will find bits of pebbles on their own but many soils don’t have the right size or enough. Get poultry grit and feed free choice in a pan in a covered location and you know they will be healthy. Then if you have laying hens whose eggs are mostly calcium (85-90%) you must feed crushed oyster shell (free choice covered location in separate dish) or your eggs will get very thin shelled. If the eggs aren’t of sufficient thickness, they can get bound up too plus who wants an egg that has a jelly like shell. Do not mix them nor put in their with their regular food. Back to gardening - plants need calcium to grow strong and lavender loves calcium and sharp drainage so you want both horticultural grit and ground oyster shells. Hope that helps.

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