Thursday, 11 August 2011

To over-pot or not, that is the question.

A couple of months back I did a post on search for the perfect plant pot. It's not just aesthetics that are important when thinking about keeping succulents though; the most common discussion is terracotta verses plastic. Something I think is as important is the size and shape of the pot as it is another myth that all succulents do fine with restricted root systems. Getting the pot wrong can really slow the plants growth down, which in some cases can be an advantage but not if you are actually wanting your plants to grow.

I have said it before and no doubt I will say it many more times: keeping a close eye on your plants, whether it is watching for signs of pests or disease, their water requirements, how they cope with climate etc, ultimately gives you much healthier plants. There are plants that like to be pot bound, those that need deep pots, and those that need as much root space as possible. Ultimately it would be great if this information was available in books or online, but until then you often have to learn through trial and error. I have found with my plants that yuccas like deeper pots, agaves don't mind being pot bound in full or half depth pots, aloes respond to over-potting and echeverias there is no hard and fast rule. But there are always exceptions to this.  Agave montana for instance like to have root space and grow much quicker in the ground than in pots. This may be as much due to their requirements for more water than most agaves and bigger pots dry out much slower. The plant in the photo is now almost twice the size of a second plant bought at the same time but kept in a pot.

With aloes I tend to start by putting them into one of three groups.  The tree and very large aloes like aloe plicatilis or aloe speciosa need plenty of root space.  The large rosette style vary the most; aloe saponaria likes big pots, while aloe zebrina and aloe striata cope with restricted root growth. Then the small and new hybrids like aloe snowflake and the Kelly Griffin hybrids tend to be fine in the half height pots.  One sign they may respond to over-potting is to look at the roots when you re-pot. The photo on the right shows the roots of an aloe mawii that despite being re-potted in April was already showing roots though the bottom of the pot.  This weekend I took the plant out of its pot to have a look, the pot was already almost totally roots. I re-potted it into a much bigger pot as a test.

 Whenever I over-pot a plant I always watch it closely to see if I notice any quicker growth.  There is a line between providing space for root growth and ending up with root growth at the expensive of top growth. So I'll keep a close eye on the aloe mawii for the next year or so to check that it does indeed grow quicker. Now it is in a nice pot I can also keep it out as a feature. It took me a long time to track down having seen photos of adult plants and the unusual flowers that stick out horizontally from the plant.. I am looking forward to seeing how it develops.  This is one you can stress and in low water / bright sun conditions it turns an lovely red colour. Right now it is one of my favourite aloes so I wont mind giving it pride of place for a bit.

Apart from speed of growth the other area where pot size may make a difference is in producing offsets.  There are some people that think that restricting root space means plants produce more pups,  others say over-potting encourages it. For me the jury is still out; I have plants that pup profusely and others that don't pup at all and I am a long way from being able to say how pot size effects this.  The only way pot size effects pups for me is in easy of removing and spacing.  But as I tend to remove pups at the start of each spring when I re-pot this doesn't make much difference. I would love to hear if anyone has noticed anything one way or another.

Of course water and climate usually have a far bigger effect on the speed of growth than pot size.  But in the UK where we don't have the very hot summer, or intense sun light every little bit helps.


  1. I'm using aloe vera for my thinning hair and I am very satisfied with the result.

    Cassy from Guitar Made Easy

  2. Excellent post. Pots are very much trial and error. (For me, mostly error.) I've had to start taking notes on what works and what doesn't. So many variables to account for. I switched to a true succulent potting mix and now must water at least once a week if not more.

    Your Aloe mawii is a beauty and looks great in that pot.

  3. Cassy: I used aloe vera for sunburn when I grew it, but lost the plant when I left it out over winter by accident.

    HB: We have had no summer with only about 4 hot days, so have not had to worry about my pots at all water wise. I am not sure I could cope with the amount of watering they would need if I had your temps.

  4. Where did you get your aloe Mawii? I am desperately seeking plant or seed this spring and cannot seem to find any for sale, just tantalizing posts by people who already have them! ;)

    1. Hi Margaret, I got mine from this website in France. Well worth looking at if you are in Europe.

  5. Thank you. Unfortunately, I live in the USA.