Can someone tell me exactly how this is done. I've tried this once, but I probably didn't do it correctly.
1. What is the height, when compared to the pots, of the water supposed to be? I left a few terracotta pots submerged up to a fifth of its height and the surface was still dry upon inspection a few hours later.
2. How long do I leave my cacti in standing water? Do I leave the pots in the water until it reaches the surface?
3. When using liquid fertiliser, do I feed in a similar manner?
4. I hear this method is preferred to the traditional way. One reason is because it promotes root growth, since the roots will have to 'search' for the water. But I didn't think root growth can be described in terms of a few hours or even days, but then again I don't know how much time bottom watering takes or about root growth.
5. If bottom watering proves to be better than the traditional method, to what extent is this true? I wonder if someone would like to comment on this even qualitatively. Wouldn't it be interesting to experiment with a substantial sample size to determine if there is statistical significance.
6. Does bottom watering occur naturally? Sorry to be blunt but rains falls from the top and cacti grow on soil that are free draining.
Thank you for your help.
Roger
Bottom Watering
Bottom Watering
Paralysis by analysis...sigh
in my opinions and in my climate this is what i think about it.
1. depends on how wet you want it and how well the roots are developed and what species. to completely soak the sub i found 1/2 or more is needed to ge tit done in any kind of timely manner.
2. until enough water goes in that you want...again depends on species, pot size, substrate and climate. Here with all gravel/grit/pumice substrates i soaked 100%, as it dries here in a day no matter how wet the pot is.
3. I cant say for sure, but i would worry a bit about salt build ups, but cacti are not fertilized that much so its probably fine. Personally i like pellets ad slow release, so someone else with more experience should say what they think
4. personally i find that theory BS. The theory being the water is at the bottom and the roots will grow down to get it....BUT pots are small and bottom watering soaks most of the substrate so it doesnt work that well....also roots react to gravity and they grow down anyway, so i dont see the effectiveness that well...especially with such slow growers.
5. im not sure, i like top watering better...for one it helps "flush" the substrate (something more important with faster growers especially if using liquid ferts). i also like using slow release which is more effective to water from the top to push the nutrients down. it is also far easier to control how much water goes into each pot, something i found very important with certain genera like ariocarpus and astrophytum. Lastly, bottom watering shares water will all the plants that get done at the same time, which helps spread pests and disease (very bad possibilities if you use large benches like this).
but that is avoided by doing them separately...which eats up a LOT of time!
6. they only time i can see it is in more tropical areas where they are by water sources (marshes, rivers or whatever) and have good root mass to go down for water as well (Hylocereus comes to mind)...but i doubt any cactus relies on it...someone else may know better....they already take in moisture from the air and are adapted to taking droughts and storing water...so i dont think they are built for searching down far for water....i dont *think*
just my thoughts the main reason i dont use it is because it is SO much slower than top watering, unless benches/trays are used...which work very well so long as pests and disease are kept on top of and the species work in that situation (i used to use them for propagating shrubs, and it was nice...but one attack of various origin and the whole thing is a nightmare!).
1. depends on how wet you want it and how well the roots are developed and what species. to completely soak the sub i found 1/2 or more is needed to ge tit done in any kind of timely manner.
2. until enough water goes in that you want...again depends on species, pot size, substrate and climate. Here with all gravel/grit/pumice substrates i soaked 100%, as it dries here in a day no matter how wet the pot is.
3. I cant say for sure, but i would worry a bit about salt build ups, but cacti are not fertilized that much so its probably fine. Personally i like pellets ad slow release, so someone else with more experience should say what they think
4. personally i find that theory BS. The theory being the water is at the bottom and the roots will grow down to get it....BUT pots are small and bottom watering soaks most of the substrate so it doesnt work that well....also roots react to gravity and they grow down anyway, so i dont see the effectiveness that well...especially with such slow growers.
5. im not sure, i like top watering better...for one it helps "flush" the substrate (something more important with faster growers especially if using liquid ferts). i also like using slow release which is more effective to water from the top to push the nutrients down. it is also far easier to control how much water goes into each pot, something i found very important with certain genera like ariocarpus and astrophytum. Lastly, bottom watering shares water will all the plants that get done at the same time, which helps spread pests and disease (very bad possibilities if you use large benches like this).
but that is avoided by doing them separately...which eats up a LOT of time!
6. they only time i can see it is in more tropical areas where they are by water sources (marshes, rivers or whatever) and have good root mass to go down for water as well (Hylocereus comes to mind)...but i doubt any cactus relies on it...someone else may know better....they already take in moisture from the air and are adapted to taking droughts and storing water...so i dont think they are built for searching down far for water....i dont *think*
just my thoughts
the main reason i dont use it is because it is SO much slower than top watering, unless benches/trays are used...which work very well so long as pests and disease are kept on top of and the species work in that situation (i used to use them for propagating shrubs, and it was nice...but one attack of various origin and the whole thing is a nightmare!).Stephen Robert Irwin: 22 February 1962 – 4 September 2006. Rest In Peace.
Bottom watering small seedlings is great, on average up until about 4 months old or so, much longer with Blossfeldia, Strombocactus, etc.
I imagine there's no reason to bottom water adult plants, other than very powdery glaucous ones like Dudleya (so as not to splotch or wash off the coating) or super white woolly sorts (so as not to discolor the "hair"). I'll be interested to hear what others have tried.
peterb
I imagine there's no reason to bottom water adult plants, other than very powdery glaucous ones like Dudleya (so as not to splotch or wash off the coating) or super white woolly sorts (so as not to discolor the "hair"). I'll be interested to hear what others have tried.
peterb
Zone 9
I bottom water most of my plants a couple of times per year. Keep in mind that I live in Arizona where it is very, very dry and oftentimes very, very hot. Any other environment will probably yield different results.
I put them in a container that I can fill up to the brim of the pot. So, I see water on the soil surface. I usually have to add water after the pots have been soaking for a little while to bring the water level back up.
The length of time depends on what I'm doing while I'm watering. I usually leave them for about 10 minutes or so. Definitely not an exact science for me. If you have lots of time, just keep watching until you don't see bubbles coming out of the soil.
I generally use liquid fertilizer but I don't fertilize with the bottom watering. If I found a granular or time-release that I was confident in, I'd probably use it.
One of my reasons for bottom watering is to leach some of the salts/calcium out of the pots and soil. After a few months the terra cotta pots start to show white crust. In both plastic pots and terra cotta I get crust on the top dressing and drain holes. When I do my soak a lot of that goes away. I also acidify the naturally alkaline tap water we have here in AZ. I try to get it about neutral.
I can't really address 4 & 5. As I mentioned above, I use it primarily to try to clear out salts and calcium and to give the plant a really good watering.
Bottom watering occurs all the time in nature. In the desert rain is not very frequent, but water continues to flow underground for a significant period after rain.
I use Turface MVP (calcined clay) in my cactus soil mix and I think a good bottom watering helps fully hydrate these nuggets. Bottom watering soaks all of the soil in the pot, top watering generally will not saturate all of the soil.
I also use this method when I have a plant that is dehydrated for whatever reason.
All that said, I primarly top water, using a small hose to put the water right at top dressing level, not on the top of the plant. I will occasionally water the top of the plant to get dust/dirt off. The water here in AZ tends to leave hard water marks, so I avoid that if possible.
Your mileage may vary!
I put them in a container that I can fill up to the brim of the pot. So, I see water on the soil surface. I usually have to add water after the pots have been soaking for a little while to bring the water level back up.
The length of time depends on what I'm doing while I'm watering. I usually leave them for about 10 minutes or so. Definitely not an exact science for me. If you have lots of time, just keep watching until you don't see bubbles coming out of the soil.
I generally use liquid fertilizer but I don't fertilize with the bottom watering. If I found a granular or time-release that I was confident in, I'd probably use it.
One of my reasons for bottom watering is to leach some of the salts/calcium out of the pots and soil. After a few months the terra cotta pots start to show white crust. In both plastic pots and terra cotta I get crust on the top dressing and drain holes. When I do my soak a lot of that goes away. I also acidify the naturally alkaline tap water we have here in AZ. I try to get it about neutral.
I can't really address 4 & 5. As I mentioned above, I use it primarily to try to clear out salts and calcium and to give the plant a really good watering.
Bottom watering occurs all the time in nature. In the desert rain is not very frequent, but water continues to flow underground for a significant period after rain.
I use Turface MVP (calcined clay) in my cactus soil mix and I think a good bottom watering helps fully hydrate these nuggets. Bottom watering soaks all of the soil in the pot, top watering generally will not saturate all of the soil.
I also use this method when I have a plant that is dehydrated for whatever reason.
All that said, I primarly top water, using a small hose to put the water right at top dressing level, not on the top of the plant. I will occasionally water the top of the plant to get dust/dirt off. The water here in AZ tends to leave hard water marks, so I avoid that if possible.
Your mileage may vary!
Disclaimer: I'm in sunny Arizona, so any advice I give may not apply in your circumstances.
Tim
Tim
I forgot to mention another possible reason to bottom water here in high summer: cold water directly from a hose in contact with 120-130F degree soil/pots can actually *cook* the roots, just steam them. So I'd imagine letting water warm up a bit and then having it soak in slowly might avoid that crazy side effect of living in America's furnace.
peterb
peterb
Zone 9