The Proper Way To Water A Potted Plant

[Ironryon]

Hi Emilya
Thanks for writing this....its great to a newbie to soil like me.
I'm used to hydro but on this occasion I've dared to try and grow out some AK47 I have in soil.
I realised I'd misunderstood the feed amounts on a floranova veg bottle...and over fed them by quite a bit. They're just in their 2nd week of flower. To correct this mistake I waited until the pots felt light and the moisture meter said close to dry and watered the pots with a very weak (1.0 ec) bloom nutrient mix. The water I collected in my trays under my pots after I did this were 1.6 ec and ph 5.8. I guess 1.6 is still too strong for them. The plants look on the pale side and some leaves have gone a bit yellow. I plan to add veg feed again, on th weak side to bring that ec down more. Maybe you can tell me if I'm following the right path...The other thing more related to your post though was my confusion on how much to water when I do water...
Should I water so much that I always get run off? My run off last time was substantial, it filled my trays/saucers which I'd say is about 500ml. Btw my pots are 20l. I just felt like I was adding a lot of water to get this run off and I don't like to think I'm over watering my plants which may lead to mould or root rot. The plants apart from looking a bit pale have leaves pointing upwards which is at least a good sign.

 

[Emilya Green]

Hi Emilya
Thanks for writing this....its great to a newbie to soil like me.
I'm used to hydro but on this occasion I've dared to try and grow out some AK47 I have in soil.
I realised I'd misunderstood the feed amounts on a floranova veg bottle...and over fed them by quite a bit. They're just in their 2nd week of flower. To correct this mistake I waited until the pots felt light and the moisture meter said close to dry and watered the pots with a very weak (1.0 ec) bloom nutrient mix. The water I collected in my trays under my pots after I did this were 1.6 ec and ph 5.8. I guess 1.6 is still too strong for them. The plants look on the pale side and some leaves have gone a bit yellow. I plan to add veg feed again, on th weak side to bring that ec down more. Maybe you can tell me if I'm following the right path...The other thing more related to your post though was my confusion on how much to water when I do water...
Should I water so much that I always get run off? My run off last time was substantial, it filled my trays/saucers which I'd say is about 500ml. Btw my pots are 20l. I just felt like I was adding a lot of water to get this run off and I don't like to think I'm over watering my plants which may lead to mould or root rot. The plants apart from looking a bit pale have leaves pointing upwards which is at least a good sign.

Hi Ironryon, welcome to the forum!

Part of the confusion I think comes from the differences between hydro and soil. Nutrients designed to work at hydro pH levels don't work very well in soil, which requires you to work between the pH range of 6.3-6.8. I would venture a guess that the major problems that you are seeing have to do with the pH of your incoming fluids. Don't worry about the ec of the runoff or its pH... it has just percolated through all that soil and its readings are pretty meaningless to you at this point. Just make sure that you have mixed your nutrients correctly and you have the pH adjusted to 6.5 before you apply it to the plants... and that part of this thing should be right where you need it to be.
Regarding how much to water, our goal is to saturate the soil in that container and change the pH to that of the incoming fluid. When we saturate the soil, it is holding its maximum weight of water and nutrients, and any extra will run out of the bottom. If you have done this correctly and slowly enough, you can see exactly when that point occurs, and there is no need to water so much that a large amount of excess flows out into the drip trays. I water using about 3 cups at a time per plant, and then I move on to the next plant. The very maximum that could flow out of my soil as runoff would be the last 3 cups added, and in a 14" drip tray, that is very little. If you are getting an excess amount of runoff you are watering too fast. Slow down, it is not a race. If you are just pouring a lot of water through your containers quickly, you are not saturating the soil, and your plants will never be able to take full advantage of its ability to hold water and nutrients.
And that is the other major difference between hydro and soil... in hydro, the only nutrients the plants have access to is what is in the soup. Think of soil however as a sponge, that has the ability to hold not just water, but also nutrients, in between waterings. Generally in soil you would never give nutrients every time, because it will build up in the soil, choking the roots. Most successful soil gardeners water with nutrients every other time at the most, knowing that plain pH adjusted water between nutrient waterings, allows the stored up or left over nutrients in the soil to be used ... a second dip in the well as it were, and most experienced growers will tell you that less is more.
One last comment about runoff. You will find many growers recommending a 10-20% runoff each time you water in order to constantly flush unused nutrients and salts out of the soil with each watering. In my organic grows I dont have to worry about salt buildup, so I also don't worry about runoff and generally try to avoid having a lot of it. Someone however using heavy synthetic nutrients in soil will have a need either to constantly flush using a percentage of runoff each time, or regularly scheduled full 3x flushes with fresh water. If you use the 20% into the drip trays method, you then need to suck up that water and get it out of the area. I use a turkey baster and a bucket when this happens. Did someone say that growing good pot was going to be easy?

 

[Ironryon]

Hi Ironryon, welcome to the forum!

Part of the confusion I think comes from the differences between hydro and soil. Nutrients designed to work at hydro pH levels don't work very well in soil, which requires you to work between the pH range of 6.3-6.8. I would venture a guess that the major problems that you are seeing have to do with the pH of your incoming fluids. Don't worry about the ec of the runoff or its pH... it has just percolated through all that soil and its readings are pretty meaningless to you at this point. Just make sure that you have mixed your nutrients correctly and you have the pH adjusted to 6.5 before you apply it to the plants... and that part of this thing should be right where you need it to be.
Regarding how much to water, our goal is to saturate the soil in that container and change the pH to that of the incoming fluid. When we saturate the soil, it is holding its maximum weight of water and nutrients, and any extra will run out of the bottom. If you have done this correctly and slowly enough, you can see exactly when that point occurs, and there is no need to water so much that a large amount of excess flows out into the drip trays. I water using about 3 cups at a time per plant, and then I move on to the next plant. The very maximum that could flow out of my soil as runoff would be the last 3 cups added, and in a 14" drip tray, that is very little. If you are getting an excess amount of runoff you are watering too fast. Slow down, it is not a race. If you are just pouring a lot of water through your containers quickly, you are not saturating the soil, and your plants will never be able to take full advantage of its ability to hold water and nutrients.
And that is the other major difference between hydro and soil... in hydro, the only nutrients the plants have access to is what is in the soup. Think of soil however as a sponge, that has the ability to hold not just water, but also nutrients, in between waterings. Generally in soil you would never give nutrients every time, because it will build up in the soil, choking the roots. Most successful soil gardeners water with nutrients every other time at the most, knowing that plain pH adjusted water between nutrient waterings, allows the stored up or left over nutrients in the soil to be used ... a second dip in the well as it were, and most experienced growers will tell you that less is more.
One last comment about runoff. You will find many growers recommending a 10-20% runoff each time you water in order to constantly flush unused nutrients and salts out of the soil with each watering. In my organic grows I dont have to worry about salt buildup, so I also don't worry about runoff and generally try to avoid having a lot of it. Someone however using heavy synthetic nutrients in soil will have a need either to constantly flush using a percentage of runoff each time, or regularly scheduled full 3x flushes with fresh water. If you use the 20% into the drip trays method, you then need to suck up that water and get it out of the area. I use a turkey baster and a bucket when this happens. Did someone say that growing good pot was going to be easy?

Hi and thanks for the quick reply....much appreciated.

I'm definitely still thinking with my Hydro head on. Soil is a very different game and thanks to your advice I understand it much better now.

I have been watering way too fast and way too much. So I guess that explains why the ph of the water I checked from the run off was exactly the same as what I'd watered it with. In my mind I was leaching out the nutrients in the soil so the more water the better. How wrong was I? Lol

I was advised by the shop I go to that I should set the pH as I would Hyro which is why I set it at 5.8/5.9. The 6.5 you mention would mean certain nutrients won't be accessible by the plant...that's thinking with my hydro head on again tho.

Btw the meter I have which tells me moisture also has a probe for pH and it's reading close to 7 in my pots. 1st time I've used one of these tools so I'm not sure how accurate it is or if it's even worth using...again using my hydro head here.

 

[Emilya Green]

IronRyon, I start off with this chart to make clear that there indeed are huge differences between soil and hydro pH needs. As you can see, in hydro we center at 5.8 and in soil we center at 6.5. The big lesson though is in how much to trust the advice of that guy in the hydro store... he possibly secretly wishes that you are not a success in soil, hence the inaccurate advice.

My advice is to use nutrients designed for soil and definitely get second and third opinions regarding anything this merchant has advised you to do.

Lastly, that little 3 way tester is pretty much useless for anything other than light and moisture readings. The pH meter on these things is first highly inaccurate, but second, mostly meaningless. PH drifts in a soil container from the moment that you water, and the soil pH will be different in different sections of the container. Soil pH drifts upwards to the pH it was designed to achieve, and most soils that number is up around 6.5-7.0. The pH of the soil below the wet/dry line however will be lower, being pulled down because of the pH of the 6.5 water that you last applied, and any interactions between it, the nutes and the components of the soil. Soil pH is for most of us (those who do not build their own soils) something we don't try to manipulate... we simply make sure that every fluid that hits the container, whether it is water with nutes, or just plain water, is pH adjusted to 6.5, every time. The soil will then take care of itself.

 

[Timmo]

If you use the 20% into the drip trays method, you then need to suck up that water and get it out of the area. I use a turkey baster and a bucket when this happens.

Is there any reason not to squirt the runoff water back into the pot until the soil just won't hold any more? Or to squirt it into the next pot? Theoretically (if I'm watering correctly), if there's runoff, the soil is already saturated, but sometimes I get to runoff and the pots still aren't as heavy as I know they should be. If I'm watering with compost tea, I'd prefer not to waste 10-20% of it, since I never seem to brew quite enough.

 

[Curly Beaver]

Is there any reason not to squirt the runoff water back into the pot until the soil just won't hold any more? Or to squirt it into the next pot? Theoretically (if I'm watering correctly), if there's runoff, the soil is already saturated, but sometimes I get to runoff and the pots still aren't as heavy as I know they should be. If I'm watering with compost tea, I'd prefer not to waste 10-20% of it, since I never seem to brew quite enough.

I have checked pH on run-off at 5.0 so no way would I run that back through.

 

[Timmo]

OK, that's a really good reason not to put it in the next pot, but I think that if the water pH got that low by running through the soil, running it through again shouldn't change anything other than adding more moisture. Should it? It'll be a few days before I water again, but maybe I'll do it with one and see how the pH changes the second time through.

 

[Emilya Green]

Is there any reason not to squirt the runoff water back into the pot until the soil just won't hold any more? Or to squirt it into the next pot? Theoretically (if I'm watering correctly), if there's runoff, the soil is already saturated, but sometimes I get to runoff and the pots still aren't as heavy as I know they should be. If I'm watering with compost tea, I'd prefer not to waste 10-20% of it, since I never seem to brew quite enough.

when this happens Timmo, make a mental note to slow down even more next time. Some soils have a flow through rate that is too high, like when you add too much perlite, and it becomes much harder to get the water to slow down long enough to be absorbed by the organic materials in the soil. When you know that your soil mix can hold more weight, but you are still seeing flow through, try watering with smaller amounts and much slower. Try giving only a cup of fluid at first, and go smoke a joint to let it soak down into the top layer. Come back 10 minutes later and add another cup, and walk away. Go watch a tv show. Come back in a half hour, and add some more.

My soils need to be light enough so that the roots are not compacted. This then gives me a flow through rate fast enough that if I came in and dumped a half gallon on my soil, it would flow right through and I would immediately get a pool in my drip pans. Watering however is a ritual for me that is taken very seriously and very slowly. Typically I will start watering my room at 10pm and I am not done until around 1am as I multitask around the grow room, enjoy evening TV and getting ready for bed.

 

[Emilya Green]

OK, that's a really good reason not to put it in the next pot, but I think that if the water pH got that low by running through the soil, running it through again shouldn't change anything other than adding more moisture. Should it? It'll be a few days before I water again, but maybe I'll do it with one and see how the pH changes the second time through.

It is generally advised not to use the runoff water. Forget the pH for a second and just consider the aerobic bacteria that live in that moist nutrient rich drip tray. Then consider the molds, salts, carbon and other sludge that is washed out of the soil... you really want to add that back in?

Just go slower. Treat watering as an act of Zen. Patience above all else. Try to move at the speed of your plants... there are lessons to be learned in this accomplishment, such as the ability to suspend water (and microlife) in your containers, right up to the tip top, defying gravity.

 

[Timmo]

when this happens Timmo, make a mental note to slow down even more next time.

How'd I know you'd say that?

It was mostly an academic question--I've only done it a couple of times. The sludge has always been the concern.

 

[Ironryon]

IronRyon, I start off with this chart to make clear that there indeed are huge differences between soil and hydro pH needs. As you can see, in hydro we center at 5.8 and in soil we center at 6.5. The big lesson though is in how much to trust the advice of that guy in the hydro store... he possibly secretly wishes that you are not a success in soil, hence the inaccurate advice.

My advice is to use nutrients designed for soil and definitely get second and third opinions regarding anything this merchant has advised you to do.

Lastly, that little 3 way tester is pretty much useless for anything other than light and moisture readings. The pH meter on these things is first highly inaccurate, but second, mostly meaningless. PH drifts in a soil container from the moment that you water, and the soil pH will be different in different sections of the container. Soil pH drifts upwards to the pH it was designed to achieve, and most soils that number is up around 6.5-7.0. The pH of the soil below the wet/dry line however will be lower, being pulled down because of the pH of the 6.5 water that you last applied, and any interactions between it, the nutes and the components of the soil. Soil pH is for most of us (those who do not build their own soils) something we don't try to manipulate... we simply make sure that every fluid that hits the container, whether it is water with nutes, or just plain water, is pH adjusted to 6.5, every time. The soil will then take care of itself.

I completely forgot about the difference of pH for soil and hydro...didn't help the guy in the shop telling me all mediums require 5.8...I kind of trusted his advice just because he seems to know his sh*t.

I have a book called Supercharge your garden. It's been collecting dust for a while but on reading the section on soil and pH and watering this morning it backs up eveeything you've told me!! Thanks so much for sharing your knowledge...I feel I have a much better understand now of how to take care of my soil and roots etc.

 

[weenmeoff]

Hi Emilya!

Thank you for the informative posts/thread! I like spending time with my plants so this method is perfect. Unfortunately, I went from solo to 5 gallon but this is my maiden voyage so will properly up-pot next time. So much to learn....

Thanks again!

 

[SHRuuM]

On the subject of watering, I would like to bring up a tool every gardener who plants in soil needs to know, Polymers. Although Polymers are associated with plastics, certain Polymer crystals are ideal for gardening. These inert little crystals when exposed to water, or your favorite formula of feed, expand 50 fold. The picture below was just 6 TSPS and expanded to 3.5 cups of spongy goodness. In a 6" or 8" pot you use only a half a tablespoon of crystals mixed in thoroughly in your soil. In a 10" only 1 tablespoon is required. When watered they will expand and hold the fluid until the plant calls for it. This will help with run off and save money. They will also cut down watering drastically. I've been using these in guerilla farming for over 30 years and believe me, when you're humping water on a daily basis in 100 degree Texas heat you need all the help you can get. I've looked around 420 forums and don't see a mention of them so I figured this thread is the perfect place to get the info out on these little miracles.

I found these on Amazon.

 

[Radogast]

On the subject of watering, I would like to bring up a tool every gardener who plants in soil needs to know, Polymers. Although Polymers are associated with plastics, certain Polymer crystals are ideal for gardening. These inert little crystals when exposed to water, or your favorite formula of feed, expand 50 fold. The picture below was just 6 TSPS and expanded to 3.5 cups of spongy goodness. In a 6" or 8" pot you use only a half a tablespoon of crystals mixed in thoroughly in your soil. In a 10" only 1 tablespoon is required. When watered they will expand and hold the fluid until the plant calls for it. This will help with run off and save money. They will also cut down watering drastically. I've been using these in guerilla farming for over 30 years and believe me, when you're humping water on a daily basis in 100 degree Texas heat you need all the help you can get. I've looked around 420 forums and don't see a mention of them so I figured this thread is the perfect place to get the info out on these little miracles.

I found these on Amazon.

If you let the soil dry out, will these polymer crystals shrink back down and leave behind large air pockets in the soil?

 

[SHRuuM]

If you let the soil dry out, will these polymer crystals shrink back down and leave behind large air pockets in the soil?

Yes they shrink back but no they don't leave large air pockets behind. The crystals are small and you don't use great big clumps. They are the size of Perlite and you only use a small amount mixed thoroughly in the soil, so dispersion doesn't allow pockets when they shrink back.

 

[Emilya Green]

does microlife get trapped in this stuff and therefore become rendered useless in digesting organics and transferring raw materials to the roots? This is why I like perlite, it gives moisture and microlife a place to hide when conditions get dry, but does not trap it.

 

[Radogast]

does microlife get trapped in this stuff and therefore become rendered useless in digesting organics and transferring raw materials to the roots? This is why I like perlite, it gives moisture and microlife a place to hide when conditions get dry, but does not trap it.

I would think it would add more texture to the soil, providing homesites for some members of the soil community in search of a polymer crystal sized home.

 

[SHRuuM]

does microlife get trapped in this stuff and therefore become rendered useless in digesting organics and transferring raw materials to the roots? This is why I like perlite, it gives moisture and microlife a place to hide when conditions get dry, but does not trap it.

I can't say if they do or do not give a place for microlife, but after 30+ years of use with NO detrimental effects to the plants, I can say this stuff is very beneficial. Think of them as an inert sponge absorbing water and nutrients to a very large degree that perlite cannot come close to. IMHO perlite is more of a device that keeps the soil from clumping up, not an oasis for roots to get their nutes at their own rate. And yes they do add texture to the soil and helps aeration in expansion and contraction. I am surprised no one knew of polymers, since they were first touted in the early '80's by Ed Rosenthal and Mel Frank, the first gurus of growing weed. Its just another tool for the grower's arsenal. Knowledge is power.

 

[Emilya Green]

I can't say if they do or do not give a place for microlife, but after 30+ years of use with NO detrimental effects to the plants, I can say this stuff is very beneficial. Think of them as an inert sponge absorbing water and nutrients to a very large degree that perlite cannot come close to. IMHO perlite is more of a device that keeps the soil from clumping up, not an oasis for roots to get their nutes at their own rate. And yes they do add texture to the soil and helps aeration in expansion and contraction. I am surprised no one knew of polymers, since they were first touted in the early '80's by Ed Rosenthal and Mel Frank, the first gurus of growing weed. Its just another tool for the grower's arsenal. Knowledge is power.

vermiculite holds water too, but I do not use it in my living soils because it seems counterproductive to restrict the little microbeasties like that. For a synthetic nutrient grower, who does not mind that he/she is turning his soil into a quasi hydro system by artificially forcing it to hold water, these ideas have possibilities... keeps the nutes in contact with the roots longer, probably holds some oxygen too.

So anyway, thank you... a thread discussing how to water in a container should also include a discussion of these kinds of super absorbent zero flow through mediums. We could also discuss the two completely different ways of using coco... your watering method definitely needs to change depending on the grow medium you are using.

 

[UIHuigh]

Many thanks, great information .