Avoid Overwatering

M

mobarley

New Member
Hi people,

I hope I am posting this in the correct sub-forum...

After reading so many posts about over watering, root rot and gnats on this and other sites dedicated to indoor growing of weed, flowers, vegetables, etc. I felt compelled to write this post.

I can not get why so many people recycle this same old piece of incorrect misinformation - "stick your finger in the soil up to the 2nd/ 3rd knuckle and if it dry it's time to water" That one sentence has probably killed more plants than Monsanto and Round Up.

Here's the reality - If you grow anything whatsoever indoors, in a container of 3 gallons or more, and you follow this advice you will kill these plants from over water, root rot and gnats EVERY SINGLE FRIKIN TIME.

That may work if your growing basil in a 16 OZ cup. As far as a large plant in a large container goes -
The top few inches of soil can be dryer than the sand in the Empty Quarter during a wind storm down to your 3rd knuckle and still be totally saturated in the bottom 6 or 8 inches of medium.

For example, I have grown tomatoes and cucumbers in four , five, six and seven gallon pots and I can stick a moisture meter down 8 inches and get a zero reading when the bottom of the container is still completely saturated.

Why people keep posting this none sense is a mystery to me.

OK then - How do you know when to water:

Number one - get a frikin moisture meter . They cost a whopping six or seven bucks. You can also put a testing hole closer to the bottom to check that area if you need to when your first getting the hang of things.
Number two - This is something you must get familiar with even if your to much of a cheap ass to get a meter. . . . Fill a like size container with the same medium that it totally dry and don't water till you plants are closely approaching that same light weight.

To put this in perspective - I can take a 1 month plant from a 3 liter container and transplant it to a five or six gallon container and it may take up to a solid 4, 5 or even 6 weeks before it needs more water. In other cases, it may only take one or two weeks. It depends on the plant type, humidity, growth rate, temps, water holding capacity of medium and other factors. This is why you need to employ the two steps above. There IS NO FORMULA to accurately guess the time between watering without checking the medium.

I hope this can help someone new to container gardening.

PEACE !
 
I agree. There's a lot of less-than-sound-advice being given out here lately and the "stick your finger in the soil" thing is not very effective or accurate. Nonetheless, that's the first thing I typically see recommended whenever anyone asks about watering. If you have a 10 gallon pot, don't you think there might be moisture below the first 3 inches of soil? I mean, that's a lot of soil and we all know how gravity works. The top 3 inches will be the first to dry out because of its proximity to the lights, but down lower in the root zone it could be very wet. I advise anyone to get a second opinion before listening to ANY advice. You can even get a second opinion on that advice if you'd like.:laughtwo:

The moisture meter works well if you have no other way to know for sure if the plant needs water. Eventually a grower should get to a point where they can lift the pot and tell simply by the weight if it needs watering. This is what I do. My plants are very light when they need water, and I still wait another day just to be sure. But if you need to know with absolute certainty, get a moisture meter.
 
Welcome to the forums and thank you for sharing your knowledge i do hope it helps many people !

Yes their would appear many fine points to watering etc not all are covered...


1. Plant size to pot size.

2. RH aka relative humidity to transpiration ratio... lower RH increase's transpiration increasing uptake of moisture, ideally your environment RH should be 40% to 60% RH aprox.

3. Temperature vs evaporation of moisture due to pot size & plant.


Just other points mostly over looked which kind of makes things a little bit of fine tuning per individual on the endeavors of growing :thumb:
 
mobarley said:
Hi people,

I hope I am posting this in the correct sub-forum...

After reading so many posts about over watering, root rot and gnats on this and other sites dedicated to indoor growing of weed, flowers, vegetables, etc. I felt compelled to write this post.

I can not get why so many people recycle this same old piece of incorrect misinformation - "stick your finger in the soil up to the 2nd/ 3rd knuckle and if it dry it's time to water" That one sentence has probably killed more plants than Monsanto and Round Up.

Here's the reality - If you grow anything whatsoever indoors, in a container of 3 gallons or more, and you follow this advice you will kill these plants from over water, root rot and gnats EVERY SINGLE FRIKIN TIME.

That may work if your growing basil in a 16 OZ cup. As far as a large plant in a large container goes -
The top few inches of soil can be dryer than the sand in the Empty Quarter during a wind storm down to your 3rd knuckle and still be totally saturated in the bottom 6 or 8 inches of medium.

For example, I have grown tomatoes and cucumbers in four , five, six and seven gallon pots and I can stick a moisture meter down 8 inches and get a zero reading when the bottom of the container is still completely saturated.

Why people keep posting this none sense is a mystery to me.

OK then - How do you know when to water:

Number one - get a frikin moisture meter . They cost a whopping six or seven bucks. You can also put a testing hole closer to the bottom to check that area if you need to when your first getting the hang of things.
Number two - This is something you must get familiar with even if your to much of a cheap ass to get a meter. . . . Fill a like size container with the same medium that it totally dry and don't water till you plants are closely approaching that same light weight.

To put this in perspective - I can take a 1 month plant from a 3 liter container and transplant it to a five or six gallon container and it may take up to a solid 4, 5 or even 6 weeks before it needs more water. In other cases, it may only take one or two weeks. It depends on the plant type, humidity, growth rate, temps, water holding capacity of medium and other factors. This is why you need to employ the two steps above. There IS NO FORMULA to accurately guess the time between watering without checking the medium.

I hope this can help someone new to container gardening.

PEACE !
Click to expand...

This is all very true for soil and organics. I stick my finger in one of the drain holes at the bottom to make sure its dry. If it's dry or just barely damp, I water it. Never had a problem with over watering using that method. As I think everyone has mentioned, the two handed lift is priceless

but hydroponics is a different story. No matter how much is "looks" like soil (aka coco or hempy)
 
Hi, I am a new member and first time grower. I have my girls in soil in 10 gallon pots outdoors. They are about 4 weeks into veg. They are about 16 in. and are looking pretty good. They have been in these pots about 10 days. I potted them up sooner than I wanted due to issues I was having in the smaller pots (cheap soil that held too much water and drained badly) My issue is when to water. This post struck a cord with me as now the top few inches are bone dry but moist below that and still pretty darn wet at the bottom. I assume that most of the roots are well above the bottom. I fear that if I don't water the whole pot is nearly dry, most of the roots will have been dry for quite awhile. The weight test isn't working for me know, the pots are too freaking big for me to have a feel for it. Any help would be greatly appreciated. I'm guessing this will become much simpler when the plants are larger. But I want to get them there.
 
KodiakKid said:
Hi, I am a new member and first time grower. I have my girls in soil in 10 gallon pots outdoors. They are about 4 weeks into veg. They are about 16 in. and are looking pretty good. They have been in these pots about 10 days. I potted them up sooner than I wanted due to issues I was having in the smaller pots (cheap soil that held too much water and drained badly) My issue is when to water. This post struck a cord with me as now the top few inches are bone dry but moist below that and still pretty darn wet at the bottom. I assume that most of the roots are well above the bottom. I fear that if I don't water the whole pot is nearly dry, most of the roots will have been dry for quite awhile. The weight test isn't working for me know, the pots are too freaking big for me to have a feel for it. Any help would be greatly appreciated. I'm guessing this will become much simpler when the plants are larger. But I want to get them there.
Click to expand...

If they're plastic pots, then they should still be fairly light when lifted if the medium is dry. Roots travel faster than you think. Given the proper care and soil, I've seen roots hit the bottoms of 8 gallon pots within a couple of days of transplanting so your plants roots might very well be fine until the pot dries out. I would wait and just watch carefully for drooping. Try to check the pot every 8-12 hours or so to get an idea of how quickly the weight is changing.
 
10 gallon pot that is pretty huge & on a rough metric conversion that is some 40 to 50 liters aprox, even if watered well or to the point of the first inch or 2 of soil being dry i would have problems doing a weight test !

Still more than enough moisture in a pot that size even with the a couple inches of soil dry at the top even for a plant of 4 weeks old :thumb:


Some people may suggest to let the pot dry out a little as this will encourage the roots to go in search of moisture aka larger root mass, bigger up take of nutrients etc = bigger bud.

Over watering or to the point of over doing it is only going to create shallow growing roots, it is not a very good idea !


Smaller plants require less watering to larger plants mainly down to transpiration aka sweating through the leafs is about as simple as i can put it, some of this due to ambient temperature, relative humidity & possible wind speed in km/mph... Mmm technical stuff ah.

Don't get to wrapped up in tec stuff it is pretty easy like watch 'n' observe & learn... adjust if need be to plant size & environmental conditions.
 
Thanks guys for the invaluable help. It gives me a plan. I'm just going to keep a close eye on them like I do anyway and let the pots get pretty dry unless they tell me they need water before that. BTW, I have a couple in the ground with my vegetables, and they are loving it there. They are almost twice the size of the ones in pots. And I was surprised to see how much they are loving the hot weather. (103 F. yesterday). Again, I really appreciate the help.
 
I like to base it off of the plant. If she looks thirsty (leaves starting to droop a bit) I water. I have mine in a 5gal bucket and water every other day and feed every 4 days, and she does great. If I skip a day of water, she droops. But like you said, it all depends on the environment and the plant it self. I followed watering if the first 3 or so inches being dry, until I realized that the plant was still fine even with the top inches dry as a desert. I think you should just pay attention to how the plant acts when and when its not been watered. It is a weed, so it can take a little abuse without much damage.
 
Thanks again for the advice. I just learned watching the plants is the key, as you guys advised. During the weekend with hot weather the girls drooped some. I watered and they thanked me by standing tall again in about 15 minutes. The soil was dry about 3 in. down in the the 16 in. tall containers. They are all green, happy, and growing fast. I expect they will need water again in 2 or 3 days. Thanks again for your help.
 
For us, total grower noobs, it was actually not OVER watering but "wrong watering"....like the simplest thing you wouldn't even think to get it wrong, but we did. Let me explain.

Everyone and their mama tells you how bad overwatering is. Right?

Because of this fear we watered really "carefully" with a sprayer...until we realized that you really have to SOAK the entire pot and if you can so much that water actually comes out the holes at the bottom. If you make the same mistake as we did, your soil might maybe get moist one or two inch down but the rest will keep dry, nothing would grow like that when the roots don't get water!

Short: Use the old rule and water when you see soil is really dry 1" or so down when you stick a finger in it, but WHEN you water then water them GOOD and drench the entire pot. SIMPLE...but nevertheless we did it wrong in the beginning :)
 
Hi! I am watering my 18L pots with 1L of water every one or two days depending on the size of the plant in flowering (I grow autos), meaning there is never a runoff. Now, whenever I water my soil is not really dry like you guys say it must be, not even the first inch maybe but I don't get signs of over watering. Sometimes the laves do go down for 1-2 hours but I guess that is normal... On the other hand if I let 2 inches of the soil go completely dry the plant looks underwater. Reading this .... BUM! ... Dilemma! Any suggestions?
 
I had what I now consider an urgent unusual situation with small plants in too large a container. I was totally paranoid of over watering since I had heard all of the advice in that regard and had experience growing other plants. I got past that by watching the plants and watering when they told me they needed it. And by the next watering they had grown so much they were into their pots so to speak. Since then it has been a breeze. They are drinking the water up. My soil drains well. And I can tell when they need a drink. And by drink, I water the shit out of them when they need water. Go slow, let it absorb, water more, but definitely let it drain out the bottom good. The worst you are doing by that is wasting some nutes.
 
KodiakKid said:
Hi, I am a new member and first time grower. I have my girls in soil in 10 gallon pots outdoors. They are about 4 weeks into veg. They are about 16 in. and are looking pretty good. They have been in these pots about 10 days. I potted them up sooner than I wanted due to issues I was having in the smaller pots (cheap soil that held too much water and drained badly) My issue is when to water. This post struck a cord with me as now the top few inches are bone dry but moist below that and still pretty darn wet at the bottom. I assume that most of the roots are well above the bottom. I fear that if I don't water the whole pot is nearly dry, most of the roots will have been dry for quite awhile. The weight test isn't working for me know, the pots are too freaking big for me to have a feel for it. Any help would be greatly appreciated. I'm guessing this will become much simpler when the plants are larger. But I want to get them there.
Click to expand...

Get a cheap moisture probe with the single probe. Drill some holes in the sides of the pots every couple of inches down the side. Stick probe in at various depths to know what's going on in there. To prevent or deter gnats I would put the prob in about 4" in a 4gal pot then bottom water. As soon as the probe starts to show rising moisture stop watering and remove all excess water from the tray. Turkey baster works good for that. Then the top 2" stays bone dry. If gnats are present then the layer of diatomaceous earth I'll put on top doesn't get disturbed either. Bye-bye damn gnats! :)

I've used the weight test for many years and it never fails.

L8r
 
LadyMiha said:
Hi! I am watering my 18L pots with 1L of water every one or two days depending on the size of the plant in flowering (I grow autos), meaning there is never a runoff. Now, whenever I water my soil is not really dry like you guys say it must be, not even the first inch maybe but I don't get signs of over watering. Sometimes the laves do go down for 1-2 hours but I guess that is normal... On the other hand if I let 2 inches of the soil go completely dry the plant looks underwater. Reading this .... BUM! ... Dilemma! Any suggestions?
Click to expand...


My dear LadyMiha you are in error. I use almost exactly that size pot and they take 4 - 5L to water properly. You are only getting maybe the top third of the rootball wet while the rest is dry as a popcorn fart. As the roots grow into this arid wasteland they dry up and the tips die while those in the moister zone branch out in search of water and food.

Fear not fair damsel in distress as yon gallant knight approaches. (teehee)

If you don't already you should have your pots in a tray to catch runoff and allow them to sit in the runoff for a while to be sure the water has moistened every bit of the rootball and there are no areas in the pot that remain dry. I use a turkey baster to remove any water left over an hour after watering/feeding.

I also use a small aquarium air pump with a 4" stone running in a jug of water all the time, or at least 24 hours, to keep the water as saturated with O2 as possible before I use it.

Once you water as I said the roots will rapidly grow into the new area and within a week or so you should see roots growing out the drain holes. Give some nutes with that watering. 1/2 strength at least. I'll feed every 2nd watering.

Before you do this watering and with the plant pretty dry lift the pot a bit and feel its weight. An easy way to do this if one's back is tender or there are physical impairments is to squat down close to the plant, thighs parallel to the floor, and rest the forearms on the knees. Grasping the pot on either side rock back slightly using your knees as a fulcrum and lift the pot just a bit off the floor. Maybe even fill an empty pot of the same size with dry soil of the same type to compare the weight until you get really used to it.

Hope that helps. :passitleft:

L8r


 
I am actually thinking that the weight test (pot as a hole) is "relatively" accurate. It tells me better whether there is is still water deep in the pot than just putting my finger in the soil an inch down. I have to keep telling my wife NOT TO WATER almost every day, she always thinks "the plants are thirsty" but they're definitely not :)

And of course it totally depends on the soil. Canna Terra Pro for example holds a ton of water a long time and I can empty a gallon or more into a 7L pot and it won't drain. And under-watering and giving 'em water when they're really showing signs (slight wilting) is definitely better than over-watering. (It chockes the roots, it builds up nutes in the soil, it promotes fungus etc..)

I also think if it's so desperate that you need to cut into the sides of the pot you may possibly want to consider changing soil like adding more perlite for better drainage.

>> 18L Pot, 1L Water <<

18L is a huge pot and 1L is sure not enough for this size pot...imho...
 
OldMedUser said:


My dear LadyMiha you are in error. I use almost exactly that size pot and they take 4 - 5L to water properly. You are only getting maybe the top third of the rootball wet while the rest is dry as a popcorn fart. As the roots grow into this arid wasteland they dry up and the tips die while those in the moister zone branch out in search of water and food.

Fear not fair damsel in distress as yon gallant knight approaches. (teehee)

If you don't already you should have your pots in a tray to catch runoff and allow them to sit in the runoff for a while to be sure the water has moistened every bit of the rootball and there are no areas in the pot that remain dry. I use a turkey baster to remove any water left over an hour after watering/feeding.

I also use a small aquarium air pump with a 4" stone running in a jug of water all the time, or at least 24 hours, to keep the water as saturated with O2 as possible before I use it.

Once you water as I said the roots will rapidly grow into the new area and within a week or so you should see roots growing out the drain holes. Give some nutes with that watering. 1/2 strength at least. I'll feed every 2nd watering.

Before you do this watering and with the plant pretty dry lift the pot a bit and feel its weight. An easy way to do this if one's back is tender or there are physical impairments is to squat down close to the plant, thighs parallel to the floor, and rest the forearms on the knees. Grasping the pot on either side rock back slightly using your knees as a fulcrum and lift the pot just a bit off the floor. Maybe even fill an empty pot of the same size with dry soil of the same type to compare the weight until you get really used to it.

Hope that helps. :passitleft:

L8r
Click to expand...


When you water 4-5 liters how many days will it keep the dirt moist, I mean after how many days is the next feeding?
 
My pots are 4 gallon and take 4 - 5 days to need watering/feeding after a good soaking.

I t depends on the size of the plant and it metabolism too. A plant growing at a rapid rate will use more water than one that isn't and water use goes up with higher temps and lower RH and goes down with the reverse. That's why being able to judge by the weight of your pots works well.

The old "water when it feels dry 3 down" doesn't work so good as the pot could have lots of water in the bottom half and should be allowed to get used up before more is added.

L8r
 
Thanks so much for your help earlier OldMedUser. Once my girls got just a little bigger watering has been no problem between the weight test, finger test, and just watching them. I know when they need water, now. Basically they tell me. But I am beyond that now, they are green and growing. Two in the pots and two in the ground outside. Here in the Portland Oregon area. I would hope that you would look at my grow journal. We're getting close to flowering and I am a newbie who needs some guidance. Here are the girls. One freebie sativa in the ground, one Kaya Gold next two her. The second pics are two Kaya Golds in Pots. They are all 9 weeks. The skinny sativa is 5.5 ft. tall now. The two in the pots are about 3'. I have no idea what to do now but water and feed them. I'm using botanicare nutes. Still using Grow every other water. Could you watch and help?

Grow journal: First Time Grow Journal - Outside - Kaya Gold & Freebies

Two girls in ground:


IMG_017945.JPG


Two girls in pots 8 gallons:

IMG_021543.JPG
 
How long the soil stays moist can depend on many things:

* Your soil
* Pot size / pot type
* Climate (temps, humidity, etc.)
* Small plants/large plants?

We're using 7L (approx 2 gal) pots with Canna Terra Pro and I can tell you that there is no need to water more than say, every 3 days. (The last time I watered was Friday). The Canna Terra Pro holds water a long time. This at still very hot temps, approx 95F currently. The "best" way I found when to water is really just to lift the pots to check their weight, better than putting a finger in the soil.

And: Under-watering is always BETTER than over-watering. Roots need air etc.

>>
The old "water when it feels dry 3 down" doesn't work so good
>>

yes exactly!
 

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