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[bezevo]

usually  I wait tell late spring  to root cactus  cuttings .. 

but I  just  ordered a heat mat with a adjustable  thermostat . 

any  one have advice ,pointers or tips ?

thanks  for your time and info

[FewTrueSeed]

My advice is dont use it for cacti. Heat source=bacteria unless you can diffuse the heat properly. Still i dont think cacti need it much. I would be interested to hear contrary. 😀

1 Like HortyCulture likes this.

[Psylocke]

Nah, I just chop em up come winter and let them sit in a cool dry place till early spring. Then, pot em up and off they go. It's doesn't have to be rocket science. Save the heat mat for seedlings.

2 Likes happyconcacti and HortyCulture like this.

[bezevo]

ok thanks for info ..Psylocke and  FewTrueSeed your probably right .

ok  some more info on what I was thinking .

 When I root cactus  in warmer weather outside ,I put the cutting in dry soil ,
 
no watering for 2 weeks to  2 months .

I do this   to avoid any rot  caused by bacteria .

Once the cactus roots I begin to water .

So my thinking  was using the mat indoors in winter I could get a  head start on rooting  by  planting  the cutting in dry soil no watering  as usual .

 I was speculating that indoors in the winter  the gentle heat from below  would stimulate rooting ?  What would be Ideal air temps night and day .. and what temp would I set mat at to stimulate rooting?

 So if I am rooting in dry soil with the heat mat ,would there be any more danger of bacteria then  when I do it in sunny warm weather ..??

Any opinions  on this ?

I am in zone 5  we have long cold winters 4f  to  teens down to -10f occasionally ..

 Here summers , 4 months long temps averaging 75f to mid 90s  up to 110f  occasionally ..

also very humid  in summers .

in winter my larger cactus  go into a cool dark basement room to sleep .. out side summers .

[Psylocke]

I see.. I used to live in  5b. The only problem is once it roots, it will start to grow. Unless you have a very powerful lighting setup, that growth will be very etiliolated compared to outdoor growth. I'd suggest waiting until there are about two months of winter left so that you can get a jump on rooting, but it doesn't have time to etiliolate too much. As for rotting, it shouldn't be a problem as long as you let the soil dry out completely between waterings. If in doubt, don't water. Roots will form even with very minimal watering. Also make sure the soil is quick drying and very well aerated. Lots of coarse sand, perlite or pumice. In my area, decomposed granite is plentiful and cheap. Very good soil additive for cacti.

1 Like FewTrueSeed likes this.

[bezevo]

ok sounds good thanks

[LIBERTYNY]

 the standard 10 by 20 heat mats dont get hot enouth for  large areas, so I would keep the soil/medium to bare minimal to conserve heat.

[happyconcacti]

I'd put them in the garage/shed (anywhere colder than about 60F but warmer than freezing) and forget about em till Spring. They'll do their thing in that time and will be ready to pop when you toss em in soil and water em.

In my experience, the longer they're not in soil the easier it is to get them to root.

[Lukas123]

I just reply this old thread as it might be good info for someone.

If a cactus, say a T.Pachanoi cutting has callused completly and you now want roots to form.
If you bring it into room temperature it will produce roots much faster than if in colder temps.
It doesnt need any soil to form roots, you can put it in an empty pot for example.
Some put perlite in a pot to aid it in standing up.
It´s the gravity that make the roots form at the bottom, not soil/media under the cactus.
If it is layed down it will start produce roots along it´s side.
This can even happen if the cactus has been stored laying down before and is put standing up for rooting.
Some people think a little moisture in the perlite or media under the cactus promotes rooting.
Just be careful not to let it sit on wet media for longer periods, it will begin rotting.

I havent tried a heat mat but i doubt it will make much difference.
Maybe if it really can heat up media under the cactus a bit so a little watering make soil humid but drys pretty quick.

[New Wisdom]

Heat mats work great for harder to root plants like ariocarpus and astrophytum as long as you keep them dry ime.   For trichocereus it's completely unnecessary as they root very easily.

[geezer]

I have excellent luck early in spring by rooting cuts in black plastic pots. They absorb heat from sunlight but in a nonviolent way which seems to encourage rooting very early in the year. I'm up north so weeks matter here

I rig a partial sunscreen for the columns so they don't burn but leave the pot exposed to the sun. Good for the roots, good for the column.

Once a good root ball is under the column you can transplant to a prettier pot or whatever.

[Inyan]

I root all my cacti in a green house as I find the heat speeds up the root growth tremendously, but for those that want a slower method a heat mat would indeed speed up the growth of your Trichocereus roots.

2 Likes SKUNK and Shamichael like this.

[Cactiqueen]

I realize this topic is dead but I wanted to revive it simply to say I’m delighted that this read exsists because it confirms a recent suspicion of mine that a heat mat can speed up root growth for cacti when applied properly

I’d be interested to hear exactly how the user who stated ariocarpus will root better on a heat mat goes about doing so? Perlite ontop of heat mat?? Details appreciated ty

[Shamichael]

I have rooted many cuttings this winter using a heat mat, once well calloused I used wide mouth jars with cococoir put on heat mat for a few days then add a little water and within another couple days I see roots...heat definitely speeds up roots imo.

[Cactiqueen]

Whoaaaa I’m gonna have to try this!! Ty for sharing

Was this with seedlings or larger cuttings day 4”-12”??

Either way tho I’m gonna try I have some cuts needing roots for spring yet