Kitchen Garden Forum

Hi,

Watching Gardeners World this morning made me think about when to add grit to compost.

I've just replaced my fish tank and am left with a bucket of grit. Rather than chuck it it would be great to re purpose it.

A number of herbs in pots were not successful last year and I wonder if it was drainage related (tarragon, thyme, oregano). If I mixed in some grit to the compost before replanting, would this help or be of no benefit at all?

Are there other plants which would benefit from this? Monty was adding it to compost he was putting cuttings into.

I've got enough stone at the allotment to contend with so wasn't planning on putting it there, unless you think this would be good?

Thanks in advance.

Pawty

Most plants in pots don't like water sitting around their roots, so there's not many that wouldn't appreciate a little grit, and most herbs, or plants like Lavender will thrive in a mix of 75% compost to 25% grit. For other plants you could cut the grit down to 10% and they would still appreciate it.

Apart from cacti and succulents, I have never added grit to compost in my life, could be I've been doing it wrong for over 60 years, but I'm happy with my results. I did use to put grit under Alpines in the garden to help with drainage in heavier soils on one occasion.

I endorse what OH says.
I root cuttings in a 50/50 mix of sand and plain peat.
The apparent ease with which Lupins self seed in my gravel driveway has led me to adding grit to compost when sowing these and quite a few other seeds as well. I do use peat based compost though and this seems to retain water more than other types.

Regards,
Gerry.

Afternoon Tigerbernie, i would say it is more that you water your cacti and succulents the correct amount, if grit is added it gives a little leeway if over watered....

I haven't watched GW with being away, I don't use grit for anything but I do use sharp sand. I would add some to mp compost for most things as it makes watering easier by stopping the shrinkage you sometimes get.

I agree with Geoff on this topic but there are certain applications where grit is essential.
I would say that for normal seedlings grit is not generally needed but the addition of descent sharp sand will be make a better medium to use.
JB.

I agree about the sharp sand too.... but i was just trying to answer Pawty's original question.

Hi,

Thanks everyone. I'll add it to a few and see what happens.

Pawty

There is a very great difference in price between horticultural grit and a good sharp sand but if you sieve out some sharp sand you end up with a slightly finer grit but virtually the same result. The fines from your sieving can still be added to your potting or seeding mixture. Where moisture and drainage are both required it would be probably better to use Perlite added to the mix included with the sharp sand or horti grit.

Johnboy wrote:There is a very great difference in price between horticultural grit and a good sharp sand but if you sieve out some sharp sand you end up with a slightly finer grit but virtually the same result. The fines from your sieving can still be added to your potting or seeding mixture. Where moisture and drainage are both required it would be probably better to use Perlite added to the mix included with the sharp sand or horti grit.

Good advice John, I better get sieving.