Keeping small cacti in small pots

[kal9988]

Hi - what is the benefit of keeping small cacti in small pots? I'd like to put several in one planter, but I don't want to do so at the expense of their growth. Any advice? Thanks!

[jfabiao]

I grow a lot of species that are reputedly sensitive at the root level (mexican miniatures, mostly). Keeping them in small pots hinders their growth but is a lot safer rot-wise, as the small volume of substrate dries up quicker than a large one AND is more likely colonised by the feeder roots of the plant, aiding further in the exhaustion of moisture in the soil.

In a planter plants will compete for root space and the most aggressive will probably take over at the expense of the others' growth. Expect one of the plants to do really well and the rest to wither slowly.

[kal9988]

Thanks! If the planter cacti are all small, slow-growing cacti, will there really be competition for root space?

[jfabiao]

Thanks! If the planter cacti are all small, slow-growing cacti, will there really be competition for root space?

The quick answer is "yes", but a lot of different things need to be factored in. It may happen so slow that you will move them elsewhere before one of them excludes the other, they may exploit different levels of substrate, your planter may be so big that the roots won't come in contact, etc. If space becomes a limiting factor for their development they will compete and one will win.

[kal9988]

Thanks! What if I separated the plants in the planter beneath the soil? For example, using ceramic tiles to give each plant its own "compartment" in the soil. I would then use a layer of rocks on top, so visually it would appear to be one planter. What do you think?

[jfabiao]

You would reducing even further the space available (or we may have very different ideas of what "small" means), but I suppose it would work. Just make sure you don't mess up the drainage of any of the "compartments".

[jp29]

Hi - what is the benefit of keeping small cacti in small pots? .........

It depends on how you define small pots and what you mean by "keeping". If you wish to grow small cacti to maturity indoors on narrow windowsills for instance, then you will have to select the species you grow very carefully. The benefits to be derived then are windowsills filled with exotic plants that produce flowers and fruit -- even in the middle of northern hemisphere winters -- and to contemplate and brighten up your rooms. I grow all of my miniature Brazilian cacti in 2"(5cm) and 2¾"(7cm) square plastic pots here at my house. The following link is to a web page that includes numerous photographs and cultivation information relating to this subject.

[greenknight]

Another benefit of keeping the cacti in separate pots - you can much more easily take them out of the pots to inspect the roots if a plant is looking sick. They could have root mealy bugs or root rot, you really need to be able to check.

[DaveW]

Size of pots has always been a matter of opinion and which soil to use. Plants always grow fastest in open ground that drains quickly and with free root run. However pot culture is not open ground culture and even the largest and deepest pots cannot drain down to the lower levels away from the roots the same as open ground can, so cultivation needs to be modified to suit the container.

Plants in pots are inevitably bonsai'd, but then again our plants growing on rocks in habitat in restricted pockets of soil are often bonsai'd too. That is why we often consider cacti grown on the lush side in cultivation when given rich soils or excess fertiliser are untypical of those in habitat.

There was an interesting experiment done that showed that the size of the pot does determine plant growth:-

http://www.bbc.co.uk/nature/18612661" onclick="window.open(this.href);return false;

you can always bury the small pots together in a larger container. Some of the Continental nurseries grow their large plants in pots but "bed them out" each year into beds, covering the pots so they look as though they are directly planted. This allows them to rearrange the plants every year as they grow without having to dig them all up to do so.