Consensus on sun / light exposure and watering when rooting cacti cuttings

[omr]

Hello all, new to the forum and my first topic post.

Tried searching the forum, but hoping to gather the consensus since suggestions and experience seems to vary.

My first time attempting to root mostly columnar cuttings (i.e. Cereus repandus -Peruvian Apple, Echinopsis pachanoi - San Pedro, plus a few unidentified but believed Echinopsis), and I'm doing so in terra-cotta on a balcony in the high desert (Las Vegas, NV). The source of the cuttings, plants his cuttings in ground in full sun and waters them 1 x /week, in summer. He seems to have mostly success, but I read more often instructions to keep them in shade and not water them until root formation. Then moving to full sun (or the recommended exposure, i.e. morning sun for example) once rooted. These cuttings should all likely be in full sun, even here, once rooted.

cacti_cuttings copy.jpg (199.94 KiB) Viewed 4524 times

What is the consensus when rooting cactus cuttings with regard to light exposure? Do you usually root them in full sun, or do you keep them in shade (i.e. bright, indirect exposure) until rooted?

What's the consensus on watering cacti cuttings while rooting?

...and of course the process includes allowing the cuts to fully callous, out of direct sun, with or without rooting hormone, before planting.

Thanks everyone!

[esp_imaging]

You've got lots of material, so why not try different approaches yourself, and see what works best for you?

I could give my opinion, but rooting small offsets in the UK may not be very relevant to rooting larger columnars in the Mojave desert.

[ElieEstephane]

As far as lighting goes, i'd give them so bright light. New growth is not necessarily a sign of root formation. Large cuttings like yours can easily grow and flower on their own resources.
As for watering, besides heat, i believe humidity has an important role in rooting so i like to water my cuttings sparingly after a while. Most people don't agree with this but it works for me. Keep in mind that the woodier the cutting, the longer it will take to root. So introducing humidity too early can lead to development of fungi and possibly rot.

If you are looking for a consensus you won't find any. As Ed said, you have many cuttings and can try different approaches to see what works best for you

[omr]

As far as lighting goes, i'd give them so bright light.

Can you clarify? Looks like a typo... "no" bright light?

New growth is not necessarily a sign of root formation. Large cuttings like yours can easily grow and flower on their own resources.

Excellent point. I'll remove that idea from my original post.

Keep in mind that the woodier the cutting, the longer it will take to root. So introducing humidity too early can lead to development of fungi and possibly rot.

Wonder if you can expand upon that? Could you further explain what you mean by too early?

If you are looking for a consensus you won't find any.

[omr]

You've got lots of material, so why not try different approaches yourself, and see what works best for you?

As Ed said, you have many cuttings and can try different approaches to see what works best for you

Of course I will to some extent, but that's the reason for my post - to increase my success by using the best information vs winging it... I hoped.

[omr]

I could give my opinion, but rooting small offsets in the UK may not be very relevant to rooting larger columnars in the Mojave desert.

Right, that should go without saying... I'm deleting my comment re: "Mojave Desert." But sound experience is still valuable and then can be adjusted for one's specific environmental parameters. So, I'd still like to gather as much information from experienced propagators as possible.

[omr]

Thought this was an interesting set of suggested general rules:

• The time of year has a great influence on the success or failure of plant propagation. ...As a rule, cuttings taken when nighttime temperatures are 60°F (16°C) and above will root successfully.

• Do not propagate cuttings that are badly blemished, bruised, diseased, shriveled, rotted or otherwise not clean and healthy.

• The size of the cutting will depend on the species and the size of the parent plant. Cuttings may be several feet long (Cereus peruvianus) or as small a single pad (Opuntia).

• The use of plant rooting compounds is not critical for successful rooting of many species of cacti although many commercial propagators will use them as ‘insurance’ to enhance rooting percentages.
  
  • Sulfur is often used to help ward off invasion of the cutting by pathogens.

• ...all cuttings be air dried until the soft inner tissue calluses over.

• Columnar cacti may need to be planted more deeply to achieve this goal.

• Irrigate the cuttings when the soil is slightly damp, and keep them in a bright area.

• Light levels are important. The dappled shade of a tree will often provide a great location for rooting to occur. Cuttings placed in low (light) such as under densely foliated trees will lead to thinning of the diameter of the cutting. The thinning of the diameter of the cutting will not totally disappear over time.
  
  • Some species such as Cereus peruvianus, Lophocereus, Pachycereus and Stenocereus may be rooted in direct sunlight.

• With most species, rooting should occur within 4 - 6 weeks in summer. For some species such as organ pipe cactus (Stenocereus thurberi), rooting may take several months.

• Once the cuttings are rooted, the growing tip will show signs of new growth. At this time that the cuttings are becoming ‘plump’ indicating that roots have formed and that water and nutrient uptake has occurred.

• Cuttings may be grown in 1 or 2 gallon (3.8–7.6 L) containers for up to a year without requiring transplanting.

https://extension.arizona.edu/sites/ext ... az1483.pdf