57 stone for drainage?

[BigGym]

I have a couple of cacti im tossing in dirt and realized the only gravel I have for the base of the pots is 57 stone, I believe its called. Its the same stone used for gravel driveways, roads etc. Its clean, I just wanted to make sure there wouldnt be any reactions when to roots come into contact with it. It should work out fine shouldnt it? Its only going to be an inch or so layer at the bottom of the pot. It should work fine right?

[BigGym]

Oh man I fell for it again. Well it seems gravel could be limestone which is a no go. And now I dont know if I should use the "terra cotta" claypots I have cuz apparently it can lead to root die back, but the argument against that is plastic and sealed could cause root rot. Plus the clay only has one hole in the bottom middle for drainage. And I dont have a masonry bit. I need an end all be all cactus god.

Unrooted Trich bridgesii. Terra cotta clay, one hole in the middle for drainage. No gravel on the bottom. Outdoors, good sun, proper watering, FTW?

[Steve Johnson]

Oh man I fell for it again. Well it seems gravel could be limestone which is a no go. And now I dont know if I should use the "terra cotta" claypots I have cuz apparently it can lead to root die back, but the argument against that is plastic and sealed could cause root rot. Plus the clay only has one hole in the bottom middle for drainage. And I dont have a masonry bit. I need an end all be all cactus god.

Unrooted Trich bridgesii. Terra cotta clay, one hole in the middle for drainage. No gravel on the bottom. Outdoors, good sun, proper watering, FTW?

The subject of porous vs. nonporous pots came up in January, and this is something for you to consider. Go here, then scroll down to post #13 by DaveW and my response in #14. You may find it rather interesting.

[Saxicola]

Why do you want to put a layer of gravel in the bottom of the pot? If you are thinking of doing it because of the old belief that it helps with drainage, that is no longer considered true. The only rocks or gravel I put in the bottom of my pots are specifically to block large drainage holes so that the soil doesn't wash out.

It is generally accepted that glazed pots or plastic pots are better than terra cotta except in specialized situations.

[Steve Johnson]

Why do you want to put a layer of gravel in the bottom of the pot? If you are thinking of doing it because of the old belief that it helps with drainage, that is no longer considered true. The only rocks or gravel I put in the bottom of my pots are specifically to block large drainage holes so that the soil doesn't wash out.

It is generally accepted that glazed pots or plastic pots are better than terra cotta except in specialized situations.

I use pieces of fiberglass window screen over the drainage holes, or you can use heavy shade cloth for the same purpose. Sorry, Saxi -- IMO better than how you're handling the drainage hole issue. Couldn't agree with you more on your last point!

[adetheproducer]

Where in the world are you, I use terracotta pots most of which only have 1 hole. I live in Wales so its generally damp and cold so the clay pots dry out much quicker than plastic or glazed ceramics which is good. Also I use a think layer of rocks and gravel in pots at the bottom simply To reduce the wash out and reduce the internal volume of the pot which holds water.

[Steve Johnson]

Where in the world are you,

From the opposite ends in terms of growing cacti -- your climate is so different from mine. It seems that you have the challenges of maintaining a collection in Wales figured out pretty well. Growing your cacti in pure pumice might give you the option of changing to nonporous pots, but unfortunately impossible to get horticultural pumice in the UK.

[Saxicola]

He may have meant where is the OP from. I agree that weedcloth is better than a rock, but when I'm potting I'm usually just looking to grab the first thing I see to deal with the problem. Usually that is a rock or some leaves!

[Steve Johnson]

He may have meant where is the OP from. I agree that weedcloth is better than a rock, but when I'm potting I'm usually just looking to grab the first thing I see to deal with the problem. Usually that is a rock or some leaves!

I know, I know -- that was just me hijacking another thread. Can't help myself sometimes...

[DaveW]

There was a complaint in another thread about the fine particles like sand gravitating to the bottom of the pot, so why would they not eventually clog up the pore spaces of the gravel supposedly there to increase drainage anyway? Therefore you might as well mix the gravel in with the compost and ensure better drainage to start with? A layer of gravel in the bottom of the pot for drainage seems very logical but does not stand up to proper scientific testing, something old gardeners never did therefore that drainage myth has been passed down through the generations.

http://puyallup.wsu.edu/~linda%20chalke ... ainage.pdf" onclick="window.open(this.href);return false;

http://www.todayshomeowner.com/garden-m ... ontainers/" onclick="window.open(this.href);return false;

http://urbanext.illinois.edu/containerg ... ainage.cfm" onclick="window.open(this.href);return false;

All a gravel or similar layer in a container like a pot will do is raise the trapped water level higher up the pot nearer to the roots and neck of the plant. Deep containers (just like open ground) drain much better than shallow ones since the water quickly sinks down to a much lower level away from the roots and the neck of the plant. Probably undesirable in water loving plants that most old gardeners grew, but far better for plants like ours that prefer to dry out quickly.

"Shallow containers are easily over-watered and should be checked frequently and watered accordingly. This is a must for bonsai growing in flat containers. Deeper containers drain better and grow plants better with less chance of over or under watering."

The reason for crocking pourous clay pots (a piece of broken pot over the drainage hole) was they usually had a single large drainage hole the finer soils used to wash out of. Modern plastic pots have usually replaced that with many smaller drainage holes in the bottom of the pots which do not loose the soil so easily.

I am in dull and damp old UK Ade too and if you go to any UK cactus show you will see very few in the UK now grow in anything other than plastic pots and have done since around the 1970's. If porous clay was needed we would have all changed back decades ago. I think there's just one clay pot in the links below and no glazed ceramic ones?

http://www.viridis.net/cactus/2002octshow.html" onclick="window.open(this.href);return false;

http://www.ayrcacti.org.uk/2003show/sho ... 86274#nogo" onclick="window.open(this.href);return false;"

[sabotenmen]

Daves post; Quote “All a gravel or similar layer in a container like a pot will do is raise the trapped water level higher up the pot nearer to the roots and neck of the plant. Deep containers (just like open ground) drain much better than shallow ones since the water quickly sinks down to a much lower level away from the roots and the neck of the plant. “end quote

Okay , Dave ,I’ve read about this problem many times. It left me somewhat confused. Have you ever thought how this would affect a purely mineral substrate? I use (almost) 100 % pumice in my pots. On the bottom I use a thin layer of course pumice (fine pumice would run out of the holes) and then I fill the pot with finer pumice. Would this mean that, because of my layer of course pumice on the bottom, the pumice higher up in the pot would be completely 100 percent soaked with water after watering? Excess water in a pumice substrate? I can’t imagine this! I think that when you use a 100 % mineral mix, then you won’t have to worry about a trapped water level problem at all!

[DaveW]

From what I understand it is the difference in texture of the two layers that forms a barrier. Why not do an experiment and see in the case you quote? Find one of those transparent plastic mineral or water bottles, cut it through the middle to make a transparent plastic pot about the same height as your normal pots, drilling a hole in the bottom for drainage. Layer your pumice as you would normally do in your pot, water it and then see over a few days if the difference in the grain size forms a barrier against the water draining. If it does you should see something like this link:-

http://blogs.extension.org/gardenprofessors/2013/05/" onclick="window.open(this.href);return false;

By the way the transparent mineral/water bottle pot is a good way of testing how any potting soil mix is draining since obviously you can't see through normal clay or plastic pots.

[CactusFanDan]

Growing your cacti in pure pumice might give you the option of changing to nonporous pots, but unfortunately impossible to get horticultural pumice in the UK.

Not impossible, but you have to buy it by the tonne, which isn't necessarily an option for most people.

[DaveW]

The problem with most potting ingredients in the UK is transport costs if you only want a reasonable amount. OK if your local garden centre stocks them, but if you have to order specially from any distance the transport cost can be more than the cost of the ingredient. Pumice is therefore not usually stocked by garden centres in the UK so you need to add on cost of delivery and many firms will only deliver larger lots anyway..

http://www.kaizenbonsai.com/shop/produc ... ts_id=1387" onclick="window.open(this.href);return false;

That £8.00p 7liter bag would cost you around £6.95p for delivery I think?

[BigGym]

Ok sounds good, I opt'd for plastic. And I didnt put a bottom layer of rock. I thought this was standard practice but we'll go without and see what happens.

I had a bit of an accident but Ill start a new thread for that drama we'll get these puppies growing yet.

Actually I'll toss it here too. I read to check for roots. So one i pulled up ever so gently, and it had grown 3 little inch long roots and broke out a big root from the side. However the little three cluster broke off. The soil its in is bone dry, would I be better off putting it back or letting it air dry for a week or so like when taking a fresh cutting? Any chance of infection working its way in with dry soil?