Help me to understand watering when using nutes.

Hey all,

I am in the research stage and I want to make sure I understand everything before I even think of putting a bean in dirt. I am having a hard time wrapping my head around watering of the plants and avoiding nute burn. I want to make sure I understand everything as best I can so bare with me.

Nute charts are often X ml of nutes for a gallon of water, however how do you know how much water your plant will need? Say I start a bean in a party cup and I do 1/4 strength nutes when I start seeing fan leaves. Now obviously that bean in the party cup will not take a whole gallon of water. Just to keep things simple, say the bean in the cup takes 1/4 gallon of water and there's 20% runoff.

1/4 strength nutes in 1/4 gallon of water would would mean that the bean is getting 1/16 of the ml nutes on the schedule per feeding.

I *think* that the feeding chart isn't how much a plant is to eat at one time, but rather the strength of the nutes in the water mix. Do I have that correct?

And then for the next feeding, you would want to put in the same amount of water without nutes, and test the runoff using a TDS meter. If I notice that the PPM is way low compared to the mixed nute/water PPM, it's safe to say the plant has absorbed all of the nutes in the water and is hungry for some more. Am I good so far or am I completely over-thinking this?

If you can explain it in a better way, by all means please enlighten me!

The ml / gal is the dilution of the nutes. It's not telling you how much to feed your plant but at what dilution. How much and how often you feed your plants depends on what type of soil you are using, the absorption rate of the soil and the environment RH. Whether your plant needs 1/4 gal or 1/2 gallon per feeding, the dilution (amount of nutes) will be the same.

Thank you very much for the help! So how do you guys know when feeding every watering is warranted or when to hold off and only feed water with no nutes?

You guys are the best resource!

The fertilizer should have instructions on the bottle- you can take a 'regular dose' like 2 or 3 tablespoons (about15ml) per 2 gal. watering can- of big bloom for example.
It is recommended to water that way 2 or 3 times a week.
If you want to feed or fertilize every time use a quarter dose- like 1 tablespoon or 5ml mixed with the same two gallons of water for example. If you are starting out or not following the instructions on the stuff be careful.
I have used this method with Fish emulsion and organic foxfarm (grow big and big bloom) that's about it. If you put it in a bigger pot it can use more because the roots have more surface area. Less fertilizer if it is in a smaller pot.

Probably should have mentioned that my medium will be coco coir and my nutes are GH Flora series trio.

Since coco doesn't really retain water, I should probably just nute feed every other watering and test the runoff when using plain water to see if nutes aren't being absorbed by the plant, right?

Soviet343 said:

Probably should have mentioned that my medium will be coco coir and my nutes are GH Flora series trio.

Since coco doesn't really retain water, I should probably just nute feed every other watering and test the runoff when using plain water to see if nutes aren't being absorbed by the plant, right?

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Feed coco every time, monitor your runoff ppm and adjust accordingly, if the runoff ppm is rising then back off the nutes until it stabilizes again.

Reading this thread an answers confused me to the point that I have mental block, got stressed and I am afraid to put any beans in the dirt now ( I been gardening for 30 years ).

Instead of splitting hair and using calculus to determine nutes dosage try practice on flower and veggie seeds.

Much cheaper and effective than speculating with highly complicated and foggy formulas.

Gaining confidence and keeping it simple is the base of successful growing.

Jbone77 said:

Feed coco every time, monitor your runoff ppm and adjust accordingly, if the runoff ppm is rising then back off the nutes until it stabilizes again.

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What do you think the target PPM reading would be to tell me that more food is needed?

Example: Feeding at 500 PPM (just throwing a number out there) and then the runoff is say 200 PPM. Next time I add 500 PPM juice, the coco will be around 700 which may be too hot for an early veg plant.

Buzerek said:

Reading this thread an answers confused me to the point that I have mental block, got stressed and I am afraid to put any beans in the dirt now ( I been gardening for 30 years ).

Instead of splitting hair and using calculus to determine nutes dosage try practice on flower and veggie seeds.

Much cheaper and effective than speculating with highly complicated and foggy formulas.

Gaining confidence and keeping it simple is the base of successful growing.

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haha interesting but I think you do hit on a common mantra around here: KISS--keep it simple stupid. The problem i have with that mantra is including a subjective measure like "simplicity" in a general rubric. Some people who are trained in lab procedures find measuring nutrients, pH and TDS is super simple and takes them no time at all. Some people look for more of a "water the thing and leave it alone" approach. Super results can be had from any technique that provides the things a plant needs. I'm onto organic growing after experimenting with a bunch of other styles because I like the ecosystem approach, understand it best, and find it the most rewarding. If Soviet wants to run Coco straight up--which plenty of people do--he'll need the answers he's looking for.
Good on you for doing this research and trying to understand everything before you start Soviet! But, in fairness, don't underestimate the ability to learn from experience. It might be worthwhile to get started with a tomato or other plant just to get an idea--cannabis will respond similarly and once you start to see, smell, feel what people are telling you about, you'll get the hang of it in no time.

Diatribe aside, the most common advice--and potentially most frustrating for someone starting out--is to listen to your plants. This means, pay close attention to your plants, check on them at least once a day and make observations--take down notes in your grow journal so you can have references for the future. Also, this forum provides a great way for you to journal with pictures and get advice/comments.
Finally, each strain will feed differently in different conditions. Focusing on an optimal environment first will help you a lot. Many people presume nutrient profile issues at the first sign of plant distress without recognizing some of the signs for things like heat stress, humidity stress, root binding, overwatering, underwatering all can look comparable to those nute problems.

Shortest answer: as has been pointed out, the bottle will tell you "feed every other watering" or something to this effect, and some companies will provide a detailed chart--like foxfarm--that tells you exactly what to feed when and how much of it.
hope that all helps,
Be easy,
Dr.J

also, feeding and watering are discussed as separate activities by many people. when a plant needs water, it doesn't necessarily need MORE nutrients added. it may just need a drink!

Dr.J20 said:

Diatribe aside, the most common advice--and potentially most frustrating for someone starting out--is to listen to your plants.

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Yeah, I just don't want to be those guys that start 911 posts like "OMG HELP!!!11one1" because I'm stumped. So for anyone who's grown in coco before, what is your target PPM reading when you know it's time for more nutes when watering? Or is there really no simple answer to this? I just don't want to burn my plants right off the bat.

Ive been growing in a coco/perlite mix for many years. I dont check the ppm of the runoff, it can be misleading. Just start with a low ppm and gradually increase as the plant gets bigger. I looked at general hydroponics feeding chart and it sounds reasonable, in that the ppm range doesnt sound too strong. The best way to avoid overdoing it with nutrients is just make your mix weaker than what the feeding charts say, like 50-75% strength (in a 5 gallon bucket full of water just put the suggested nutrients in for 3 gallons).

Another good way to avoid nutrient buildup during flower is once a week or so, water with a really weak mix,like 200 ppm.

It's good that youre thinking about this in advance, over feeding is really common. Ive found that with nutrient strength, it is better to give them just enough than too much. If a plant is showing a slight deficiency you can always bump up the strength to remedy it, but a plant that gets nutrient burn is hard to get back on track.

Runoff ppm in soilless growing is not misleading, it tells you if your overfeeding or not. I start my seedlings at a 250 ppm mix for 1 week and bump it 150ppm a week until my runoff comes out 100-150 ppm higher than my ingoing feed mix, I then back it off until it levels off and start again. So if im in veg and feed at 600 ppm and my runoff comes out at 800, I have overfed so il drop my next feeding until it levels off. After it levels il start bumping ppm again at say 50-100ppm until it starts coming out higher again and repeat. That way you are always feeding the plant at its optimum level and you dont burn leaves. Runoff ppm of soil is misleading but runoff ppm of a soilless medium is a great way to feed at optimum levels without guessing what your plants are actually eating.

Jbone77 said:

Runoff ppm in soilless growing is not misleading, it tells you if your overfeeding or not. I start my seedlings at a 250 ppm mix for 1 week and bump it 150ppm a week until my runoff comes out 100-150 ppm higher than my ingoing feed mix, I then back it off until it levels off and start again. So if im in veg and feed at 600 ppm and my runoff comes out at 800, I have overfed so il drop my next feeding until it levels off. After it levels il start bumping ppm again at say 50-100ppm until it starts coming out higher again and repeat. That way you are always feeding the plant at its optimum level and you dont burn leaves. Runoff ppm of soil is misleading but runoff ppm of a soilless medium is a great way to feed at optimum levels without guessing what your plants are actually eating.

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I found that to be not true (for me) and ineffective, I did it in flower though..not veg. The ppm came out higher so I would water with a diluted mix for a few days but they started looking deficient, fan leaves losing color etc so I decided to quit chasing the runoff ppm and just pay attention to the plants. For me it easier to feed on the lighter side and watch them to see how much more they can take. I get why it would work (checking runoff ppm) but it didnt really work when I tried it.

You are overthinking. First pick a good soil . I have found Fox Farms to be one of the best. Get some good plastic pots with proper drainage holes. You can use 5 or 7 gallon pots depending on the size of plant your wanting to achieve. As a rule of thumb one gallon per one foot of growth. You start with a smaller pot and let the root system fill that pot and then you transplant to the next size. This allows your plant to take full advantage of the soil and nutrients. If you put a small plant into a large pot the soil will stay wet too long because the plant is unable to use that volume. Also do not give nutrients to young plants for first two weeks. Your soil should have what they need. It is very easy to damage and even kill a young plant if you over fertilize. Go down and get Fox Farm nutrients and the schedule that they offer. If you follow it you will have good results. DO NOT EXPERIMENT. If you are a newbie than this is what you need. Just watch and learn. You must be sure to keep your ph between 6.3 and 6.8. Adjust your water ph after you add the nutrients. Hope this helps you out.

cloudhopper1 said:

You are overthinking. First pick a good soil . I have found Fox Farms to be one of the best. Get some good plastic pots with proper drainage holes. You can use 5 or 7 gallon pots depending on the size of plant your wanting to achieve. As a rule of thumb one gallon per one foot of growth. You start with a smaller pot and let the root system fill that pot and then you transplant to the next size. This allows your plant to take full advantage of the soil and nutrients. If you put a small plant into a large pot the soil will stay wet too long because the plant is unable to use that volume. Also do not give nutrients to young plants for first two weeks. Your soil should have what they need. It is very easy to damage and even kill a young plant if you over fertilize. Go down and get Fox Farm nutrients and the schedule that they offer. If you follow it you will have good results. DO NOT EXPERIMENT. If you are a newbie than this is what you need. Just watch and learn. You must be sure to keep your ph between 6.3 and 6.8. Adjust your water ph after you add the nutrients. Hope this helps you out.

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Hes growing in coco, not soil, big difference so virtually none of that applies to him

BustinScales510 said:

Ive been growing in a coco/perlite mix for many years. I dont check the ppm of the runoff, it can be misleading. Just start with a low ppm and gradually increase as the plant gets bigger. I looked at general hydroponics feeding chart and it sounds reasonable, in that the ppm range doesnt sound too strong. The best way to avoid overdoing it with nutrients is just make your mix weaker than what the feeding charts say, like 50-75% strength (in a 5 gallon bucket full of water just put the suggested nutrients in for 3 gallons).

Another good way to avoid nutrient buildup during flower is once a week or so, water with a really weak mix,like 200 ppm.

It's good that youre thinking about this in advance, over feeding is really common. Ive found that with nutrient strength, it is better to give them just enough than too much. If a plant is showing a slight deficiency you can always bump up the strength to remedy it, but a plant that gets nutrient burn is hard to get back on track.

Click to expand...

i have to agree with Jbone, that's is exactly how i feed my plants.

as he stated, ppms from runoff is far from misleading and gives the best idea of what's laying in the medium at moment of time.
what i think you meant to say is that, reading your ph from the runoff is misleading, not ppms.

Example: Water with 1/4 strength nutrients, wait till plant dries out good, then water with plain water, wait till plant dries out again, water again with plain water, wait till plant dries out again, repeat watering with 1/4 strength nutrients. If plant appears healthy after this, increase nutrients (on next water with nutrients day) with 1/2 strength nutrient watering, followed by the next two waterings with plain water. If all looks well, increase to 3/4 strength nutrients, observe plant during the next two plain waterings....and so on until you reach full strength bloom nutrients. At least this is how I do it, and I haven't burned anything yet.