I've heard it's best to make your cuttings at least 30 cm (roughly 1 ft) long, as smaller ones will grow slowly.
What's your opinion on this?

I've just cut off a 'branch' and it's 38 cm (15" ) long. I'm sure this will be a good grower, but what do you guys think about cutting it into two 7.5" cuttings?

Two 7.5" cuttings will probably be fine. The smallest cuttings I've been able to propagate were about 2" diameter and 2" long. That being said there is a dramatic difference in how fast and well a larger cutting will tend to root and pup. My general rule is to take at least a 6" cutting for propagation.

Either way is fine. But I think that you will have a better result by not dividing it. Larger cuttings tend to grow a lot faster. With smaller cuttings it just takes more time for them to get going. Cuttings that are 2 feet or longer are ideal to use for rooting. Gets you to a good-sized plant much faster. If given the choice between planting a single 15 inch cutting or two 7.5 cuttings, I would choose the 15 inch cutting everytime.

Thanks guys. I've cut it already... Next time I'll keep a longer cutting and compare.

While I've successfully propagated a 1" cutting - which was entirely due to circumstances - it surely figures that larger cuttings will have larger energy reserves. Larger cuttings also have a higher volume/surface area ratio - arguably, in effect, protecting them from dehydration and infection to some extent. Depending on the material available, my cuttings will be a minimum of 3" in length. (This is an observation, not a recommendation!)

And of course, the individual nature of the specimen of cactus has a fair degree of influence on the relative rate of pup formation, and root formation, as well as the number of pups that form. Some cacti are simply far more, er, 'puppy' than others. One particular Peruvianoid I have sends out multiple pups from even a 2" cutting, something which none of my other specimens do.

Another practically indistinguishable Peruvianoid took seven years to grow roots, although that may have been incompetence on my part. This was a scabby, skinny 5" x ¾" cutting (gifted) so really we can be pleased that it survived at all.

Mine is a T. pachanoi, a very potent and easy-rooting one strain and quite fat with a diameter of 2.75" (7cm). Thinner ones have rooted within a few weeks in the past.

any reasons other reasons why?

Do the two smaller cuttings catch up eventually? I would have thought with 2 cacti, after (n) time period you would have more cacti mass than with one. Although this may take some years.

Or would the bigger cactus always provide more mass?

Something knocked over a bit cactus I had, I now have 2x1m long cuttings broken off sections and trying to figure out the best way to go.

I have a few san pedro at the moment and definitely agree a bigger cutting seems to root quicker, puts out pups quicker and those pups grower quicker. But am not convinced that at some point, having two rooted cactis is not better than one.


If you only take a 30cm cutting. Then your initial cutting will be ready to take another cutting from in 2 years. 2 years 2x30cm 1 rooted. The initial cutting as rooted be ready for another cutting in 1 year (3 years 3 cacti, 2 rooted). At 4 years, you can cut #2, #1 ready again. So that is:
4 years 5 cuttings at 30cm (4 rooted).
total length: 5x30 = 150cm


If you take 15cm cuttings, probably can take a cutting from each at 15cm after 1 year.
year 1: 4 cacti 2 rooted
year 2 8 cacti
year 3 16
year 4 32
year 5 64

total length: 64x15cm = 960cm and 32 rooted.


Assuming my numbers are somewhat feasible (in the tropics year round growing), smaller cuttings appear better. Even if I am out on the smaller cuttings by two, it's still much better than single cuttings.

Granted this doesn't take into account the thickness of the cutting which probably does play a part, nor the fact pups grow better on a more established rooted cactus.


Actually, as I have 2 x 1m sections, I should just test it I suppose and see how it actually goes

You will definitely get more plants by using smaller cuttings. If that is your main goal then using smaller cuttings makes sense. They will eventually grow into large plants too. It will just take longer.

But I think that large cacti are much nicer than small ones. They get more potent as they get larger. They are able to be cut and bounce back a lot faster. They bloom. They can handle environmental stressors better. Its the natural state for these Trichocereus. They grow into very large, very old plants. Even at 4 or 6 feet they are still babies really. One can chop up toddler San Pedros to get high, or at least let them get to kindergarten first.