Are these healthy?

[DaveW]

Rot in container culture is mainly a function of the potting soil drainage rather than the pot. If you use mineral composts, as some do on here, and fertilise you could use almost pure grit and water every few days without rotting. If you used pure peat or heavy clay they could go for weeks without watering, even in clay pots. You can compound potting soils with every degree of porosity in between those two extremes.

Maybe you did not alter your potting mix when you went from clay to plastic pots in order to obtain the same drying times? Some even claim going from deep pots to shallow pans requires a different potting mix to achieve the same drying times.

Clay pots do dry quicker, so do suck water out of the compost, but also concentrate salts near to the pot side which attracts the roots rather than them being spread evenly through the soil as in open ground, however it is a gardeners fallacy they "breath" and allow air in through the side of the pot. If you read my previous links you will see experiments prove this false.

In the warmer parts of Spain I would think over watering plants would be hard to do unless your potting soil was very water retentive. I gave some cacti to a friend on the Costa del Sol and she waters them almost every day without rotting, in fact most of her plants are connected to an automatic drip watering system on a timer. Mind you it was 100F in the shade last time I went!

Also remember roots do not just rot from overwatering, they can rot if chemical build up occurs in the soil to toxic levels, particularly if pots are not frequently flushed out with fertiliser free water.

From the Web:-

"Plant foods are sold as salts or as salts dissolved in water. Salts are stable compounds that, when dissolved in water, can be absorbed by plants. Fertilizer solutions that aren't taken up by a plant often dry out and so revert to their salty forms. Because salts "burn" plants, they often are accused of causing tip burn.

Excess fertilizing can cause brown leaf tips. Unused salts build up in over fertilized soil and damage a plant's roots. This malady can occur even if you fertilize only now and then. If you use too much fertilizer at one time, it won't all be absorbed. Worse, a sick or dormant plant isn't able to absorb even, a normal dose of plant food. So feeding a sick plant can harm it. Root hairs that are surrounded by excess salts are injured and, therefore, aren't able to send water up to the plant. The result: the leaf tips dry up and turn brown.

It's possible to unintentionally over-fertilize a healthy plant. Some potting soils are fortified with plant foods. Since they contain organic constituents as well, they heat up inside the bag during storage. The work of microorganisms causes the release of extra nutrients and, when plants are potted up, they may get a double dose of fertilizers.

Plants potted with unfortified soil and fed only at proper intervals still can get tip burn from fertilizer. When dry soil is fertilized, roots suddenly are exposed to a very high concentration of nutrients. Clay pots all too often show another kind of salt build-up. The white crust that accumulates on the out-sides of pots is mostly fertilizer (that passes through the porous sides) and partly hard water solids. As far as has been determined, the salts that collect from hard water do not burn roots or cause plant injury except to acid. loving plants such as azaleas."

As said, not all root rot is caused by the potting soil staying wet for too long, chemical burn can also kill them.

[Driller64]

The plants themselves look healthy, but that will soon change if you don't get them out of that terrible looking soil mix. Repot into a mix with far less organic matter.

Where do I get good soil mix?

[oldcat61]

Driller - you're not that far from me. You should be able to get NAPA oil dry easily/cheaply. There's also an active Philly cactus group on Facebook; check them out. Sue

[cantharis]

Where do I get good soil mix?

You buy the components and mix it yourself.

[cantharis]

You should be able to get NAPA oil dry easily/cheaply.

¿Qué?

[oldcat61]

A lot of us in the states use NAPA Oil-Dri 8822. ( NAPA is an auto-parts chain ) as a soil amendment. I suggested it to driller since I know it's available where he lives. Sue

[TexasPricklyPiglet]

First, I would like to say, that is not a beer can. That is a candy tin, for a delicious candy known as lifesavers. Y'all should try it if you haven't already. Also, here in the states, there is a fad that concerns indoor gardeners being budget savvy. They sometimes use egg cartons to start seedlings, half a soda bottle as a pot, and the like. Maybe this person is of that mindset. I don't necessarily see anything wrong with that, although I like real pots myself. It's the soil I'm concerned about. I too use MG soil as I'm on a budget, but I take out a lot of the organic matter and mix it with sand, gravel, perlite and that. My cacti are all fit as a fiddle! It's not all bad Driller if your horse bucks you off, just climb right back on.

[Driller64]

I am one of those people who makes pots out of seemingly useless containers. I already spend a lot of money on seeds and soil, so why not save a bit on pots? I only use clay pots for my special plants that are important to me, which is why I will transplant the A. retusus plants into clay pots eventually. I will add some grit as soon as I can to the soil. I'll get some of that oil dry and perlite.

[Robb]

Oop! Sorry, forgot to check this topic . By better I was meaning that, for a start plastic pots a cheaper, but also the fact that in clay pots you don't see as much root growth down around the sides of pot. Versus in plastic the roots grow right around the sides. This is only in my experience, other people may have had different results.

[adetheproducer]

Oop! Sorry, forgot to check this topic . By better I was meaning that, for a start plastic pots a cheaper, but also the fact that in clay pots you don't see as much root growth down around the sides of pot. Versus in plastic the roots grow right around the sides. This is only in my experience, other people may have had different results.

I agree clay pots in my experience form root balls where as plastic cause root nets with the soil trapped inside. Also you tend not to get as much condensation in terracita pots.

[DaveW]

I always understood you got more root growth around the outside of clay pots and less distributed through the rest of the soil. Whereas the roots are better distributed in non-pourous containers, and scientific trials also prove this:-

"Plastic pots,

Perhaps the most significant impact of plastics in floriculture, with the exception of greenhouse coverings, is their use in the manufacture of pots. Clay was the most widely used raw material in the making of pots until the late 1960s. Jones (1931) observed that people who could not afford to purchase clay pots used nonporous containers such as tin cans and the plants flourished, while those grown in clay pots sometimes grew poorly. Jones and Haskins (1935) studied the distribution of roots growing in media in porous and nonporous containers, and reported that the root systems were almost totally outside the soil mass in porous containers, while root systems in nonporous containers were distributed throughout the media. Ball (1945), while visiting nurseries in Los Angeles, noticed excellent growth of potted plants when nonporous tin cans were used as containers. Most growers continued to be loyal to clay pots, however, as believed by Ball (1945) when he stated that, “to the end of their earthly chapter most ‘old timers’ are going to stick to clay pots.”

http://horttech.ashspublications.org/co ... 8.full.pdf" onclick="window.open(this.href);return false;

http://www.jstor.org/discover/10.2307/4 ... 4042565281" onclick="window.open(this.href);return false;

People often continue to believe what they want to believe even if controlled scientific tests prove them wrong. Plus "old gardeners myths" without any scientific foundation still abound. If your roots are not evenly distributed in plastic pots look for some other reason than the pot, your potting soil for instance.

[cantharis]

I have OTHER reasons for preferring clay pots that are not immediately obvious. My plants sit on tables outside in the summer, when we often get high winds, land breezes or sea breezes or just weather!! If I used light plastic pots - especially for those plants that like organic coir - they would be flying about everywhere. In HEAVY clay pots I get a measure of stability - an important factor for me of which NOBODY else has had the slightest consideration.

And I just plain PREFER good old-fashioned terracotta pots - especially as a supplier near me has started to provide ´Long Toms´(made in Italy!!!) - my plants do well in them, I like them, they suit my growing methods, and I will continue to recommend them to other growers !!! Proof of the pudding, etc. I really have nothing more to say on this topic - and I trust that will be the same for all other critics here.

[oldcat61]

What Steve has tried, is to waterproof the clay to give the root benefits of plastic but keep the look & weight of clay. His plants are outside like yours, so he has the same problem with stability. My problem with plastic is they are so darn ugly. Sue

[cantharis]

First, I would like to say, that is not a beer can. That is a candy tin,

Wow a candy tin - sooo MUCH better !!!!

[DaveW]

People grow plants in what they want and for various reasons of their own and that's their choice, but lets not propagate old gardeners myths as facts here which science and controlled experiments have proved fallacious. Unglazed clay pots do evaporate water through their walls. They don't however "breath" significantly by allowing air to pass the other way, as the experiment with a sucker disk remaining on one for a considerable period of time mentioned in one of my previous links proved. Because if the pot allowed air through the vacuum would have been broken and the sucker fallen off long before the experiment ended.

As Sue says many clay pot users are coating their pots inside to make them non-porous, then apart from weight they are no different to a plastic pot for growing plants in or glazed ceramic ones.

The other old myth is that a layer of gravel at the bottom of a pot helps drainage when proper experiment has proved it in fact hinders the soil above draining due to the change in texture.

Unfortunately what we often assume logically should occur is not always backed up by controlled scientific tests.