Watering cacti in mix that is mostly rock?

[Angelina]

I switched from miracle gro soil to bonsai block, Monto clay, and pine bark fines specifically for fast-draining soil, but is it too fast for small cacti? I have one which is sitting in a 2.5 inch pot, mostly filled with the block and clay. I watered it a few days ago and it's already dry. Is two weeks too long to wait to water if the mix is already dried out in this short a time? I've discussed about this cactus's decrease in size, purple discoloration, and sunburn, so I'm not sure how much it can handle.

This is where it sits now, in front of the window curtain. The last photo doesn't show the purple discoloration since it's on the reverse side. Thank you very much for all your help. I'd be so sad if I lost this cactus! It's one of my first cacti.

[greenknight]

If it's drying out within a few days, you don't need to wait 2 weeks before watering again. Maybe a week.

You do need to be cautious about watering for a while with cacti that have had the potting mix completely replaced, they need a little time to grow new roots. Plus, it's early in the growing season (which hasn't even started yet where I am, it snowed yesterday). That little guy is quite tightly potted, though (which is a good idea when you're trying to revive a sickly cactus), and the mix is very free-draining.

Has it plumped up any? It's hard to tell from the pictures, but it looks like it may have filled out a little.

[Angelina]

If it's drying out within a few days, you don't need to wait 2 weeks before watering again. Maybe a week.

You do need to be cautious about watering for a while with cacti that have had the potting mix completely replaced, they need a little time to grow new roots. Plus, it's early in the growing season (which hasn't even started yet where I am, it snowed yesterday). That little guy is quite tightly potted, though (which is a good idea when you're trying to revive a sickly cactus), and the mix is very free-draining.

Has it plumped up any? It's hard to tell from the pictures, but it looks like it may have filled out a little.

Since the barrel cactus is in the same soil, should it be watered about the same? I've recently and in the past looked up on various websites about watering, but it always greatly varies from once a week to once a month or more. I get really confused I'll be careful about how cold it gets by the window. I do usually run a heater in my room everyday.

I couldn't figure out what side of the cactus was the one I took a photo of at the beginning. I think it might have filled out just slightly because whichever side of the cactus I look at, it doesn't exactly match up to the old photo. It's weird because in person it doesn't look that much different at all.

[Edwindwianto]

I've recently and in the past looked up on various websites about watering, but it always greatly varies from once a week to once a month or more. I get really confused .

Hi Angeline

Don't get confused by once a week or once a month etc
I think the key is to wait until your substrate is none dry between each watering

You can do a simple experiment to know how many days it takes for your substrate to become bone dry

If it becomes dry every 3 days...it is save to water once every 5 days...
If it becomes dry every 5 days...it is save to water once a week...
And so on...

"Once a month", i think people only do that on winter
Because a substrate that can hold water for up to 1 month, will rot your cacti in 2 weeks (maybe)...it's too long for the cactus, a substrate that can hold water for up to 1 month

Good luck

EDWIN

[Pereskiopsisdotcom]

Edwindwianto and Greenknight have some great advice that I would definitely utilize. I can only add that from personal experience that there are no fast and hard rules for watering schedule. It depends on your conditions (amount of light, soil, humidity, air circulation, time of year, species, type of container, etc.) and only you will discover what works best for you through testing it out.

When I'm testing out a potting mix I try to test it out without a cactus in there first. I put it in the spot my cacti will grow and simulate the conditions of that grow environment (lights are on, heat is on, water like normal, etc.) When you water the empty pot you can take note of how long the moisture remains in the container, how much flows out immediately, and the number of days it takes to dry out.

[Edwindwianto]

Edwindwianto and Greenknight have some great advice that I would definitely utilize.

Thanks

[greenknight]

Edwin has the right idea, you need to go by how fast the potting mix dries out rather than a schedule. The Golden Barrel (Echinocactus grusonii) likely won't dry out as quickly because it's in a more generous-size pot and it's fully hydrated to start with.

The little one hasn't swelled up very fast because it didn't have a lot of roots. The first watering should have stimulated root growth, it may take up water much faster after the next watering. If it takes hold and starts growing well, it should be ready for a bigger pot by next spring.

Eventually, we need to ID that guy so you know how to treat it. I suspect it's an Echinocereus, maybe E. coccineus, but I'm not sure. It should be easier to tell once it's grown a bit. After you've nursed it back to health, you should take some good close-up pictures (top and side view) and post in the Cactus Identification forum.

[Jangaudi]

I don't think it's that terribly important to figure out what the highest watering frequency could be without the roots starting to rot. If you do not have any interests in getting your plant to grow as fast as possible, it's probably best to keep on the safe side. No cactus is gonna shrivel and die if you have forgotten to water it for a few days. They are made to resist long periods of drought.

[Angelina]

I've recently and in the past looked up on various websites about watering, but it always greatly varies from once a week to once a month or more. I get really confused .

Hi Angeline

Don't get confused by once a week or once a month etc
I think the key is to wait until your substrate is none dry between each watering

You can do a simple experiment to know how many days it takes for your substrate to become bone dry

If it becomes dry every 3 days...it is save to water once every 5 days...
If it becomes dry every 5 days...it is save to water once a week...
And so on...

"Once a month", i think people only do that on winter
Because a substrate that can hold water for up to 1 month, will rot your cacti in 2 weeks (maybe)...it's too long for the cactus, a substrate that can hold water for up to 1 month

Good luck

EDWIN

Hi Edwin, thank you so much for clearing that up for me! I read the linked post and I think the test is a great idea. I'll be doing that next time I water. Thank you

[Angelina]

Edwindwianto and Greenknight have some great advice that I would definitely utilize. I can only add that from personal experience that there are no fast and hard rules for watering schedule. It depends on your conditions (amount of light, soil, humidity, air circulation, time of year, species, type of container, etc.) and only you will discover what works best for you through testing it out.

When I'm testing out a potting mix I try to test it out without a cactus in there first. I put it in the spot my cacti will grow and simulate the conditions of that grow environment (lights are on, heat is on, water like normal, etc.) When you water the empty pot you can take note of how long the moisture remains in the container, how much flows out immediately, and the number of days it takes to dry out.

Thank you very much for the advice! I'll make sure to test this out soon. I'm prone to get caught up in schedules, but I'm learning now to set that aside.

[Angelina]

Edwin has the right idea, you need to go by how fast the potting mix dries out rather than a schedule. The Golden Barrel (Echinocactus grusonii) likely won't dry out as quickly because it's in a more generous-size pot and it's fully hydrated to start with.

The little one hasn't swelled up very fast because it didn't have a lot of roots. The first watering should have stimulated root growth, it may take up water much faster after the next watering. If it takes hold and starts growing well, it should be ready for a bigger pot by next spring.

Eventually, we need to ID that guy so you know how to treat it. I suspect it's an Echinocereus, maybe E. coccineus, but I'm not sure. It should be easier to tell once it's grown a bit. After you've nursed it back to health, you should take some good close-up pictures (top and side view) and post in the Cactus Identification forum.

I really appreciate the information, greenknight. Thank you! I'm going to visit the nursery it came from next month and this time I'll ask what type it is if they're still giving them away. They were actually for free there. At the time the sign only said they were babies, though. But I'll still post plenty of pictures when it's grown to check. I'm really curious.

[Angelina]

I don't think it's that terribly important to figure out what the highest watering frequency could be without the roots starting to rot. If you do not have any interests in getting your plant to grow as fast as possible, it's probably best to keep on the safe side. No cactus is gonna shrivel and die if you have forgotten to water it for a few days. They are made to resist long periods of drought.

I'll keep on the safe side, for sure. I'm really cautious about overwatering. At this point, I'd be glad to know it was growing at all, whether fast or slow. Thank you for the input.

[Edwindwianto]

Hi Edwin, thank you so much for clearing that up for me! I read the linked post and I think the test is a great idea. I'll be doing that next time I water. Thank you

Hi Angeline

NP and good luck

DDWIN

[DaveW]

If you are growing in a rocky soilless substrate Angelina don't forget you will need to fertilise every few watering's with half or quarter strength fertiliser since the plants will extract very few nutrients from your potting mix.

[Edwindwianto]

Just for sharing

I use Osmocote in my 100% mineral substrate
And it works well for me

EDWIN