Hey Gang!
I’m new to the site and excited to be apart of a community of EXPERIENCED growers!
So for my question, I’d like to know if there is any benefit to flushing my plants in flower every 3rd feed of the week or if I should just continue to feed until I see an issue with plant(s)?
Right now I just feed all the way through but I was wondering if it would be beneficial to water every 3rd feed just to make sure the soil doesn’t encounter any PH issues? I will say this, when I feed I do make sure they drain so at least nutrients are running all the way through. Thank you in advance!
The best way will be to check your medium EC on weekly or biweekly schedule . If you see increasing of the EC from week to week that means the nutes are building up in the medium .
The best methods for checking your medium EC are the PourThru method ,1:2 method and SME method . For PourThrought look for 2.0 - 2.5 ; for 1:2 method 0.5 - 0.75 and for SME 1.5 - 2.0 EC .
There is also soil/medium EC meters which are expensive and they are not accurate , stay away from them . Stay with the regular feeding if you feel that is too much nutes just cut on the strength and stay with every day feeding .
Awesome! Thanks for that! I thought about testing the PPM and converting that to EC would that work as well or is it more accurate to try the methods you mentioned?
What are you using for your growing medium and nutrients?
In general I’d check runoff often in hydroponics. EC and pH of the runoff will usually be slightly higher than what you’re putting in. There was a nice chart someone posted that explains what your plants are doing depending on your EC and pH raising and falling. If your feed and runoff are consistent (remembering the runoff will not be identical to the feed) your plants are likely healthy.
I only flush for nutrient correction or to stress the plants in late flower to up the resin content.
Yes you can do it with PPM . Just make sure the PPM meter has temperature compensation , cheap PPM meters do not have and the reading is highly depended from the solution temperature , also be aware of PPM 500 and PPM 700 , that is another common mistake !
Testing simply the runoff after fertigation is not accurate method and depends from the moisture content of the medium ( example : dry medium has very high EC and most of the salts in the dry medium will be easily washed and finish in the runoff ) , the porosity of the medium ( more porosity means more of the fresh solution will finish in your runoff ) , and finally the quantity of the run off (more run off ,more similar value to the input ) .
PourThrou is used by most professionals : 1. Saturate your medium with your regular feeding until run off . 2. Leave it for one hour to settle down 3. Pour destiled (or low EC )water just enough to get 50 ML of runoff 4. Test it and compere it with the tables that can be find on internet for PourThrou method . NOTE : Every testing method has different values and needs to be converted, with other words the ppm results that you got from testings does not corresponded with the ppm suggestions labeled on the products . And dont forget the 50ML runoff !
Thanks for the response! I’m using Coco Coir in 7 gallon pots.
When I first purchased my lights (NanoLux DE) they said I’d need to feed everyday just because of the difference in light intensity going from SE HPS bulbs to DE so I took on that approach. Before that, I fed 2 days and flushed once for that week. So because of that, I just wanted to make sure the information I was given from the light manufacturer was correct.
Aside from that, What you said is pretty much on par with how I was taught as far as flushing for nutrient correction. Your other point you made is very interesting! I always thought flushing near harvest time was to rid the plant of any remaining nutrients? What you said is good to know though!
This is GREAT info! I really appreciate it! Even though I’m not seeing huge issues where this may be the case, I’m definitely going to adopt this method just to check them from time to time.
I have RO water so I’m guessing that would work just as good or better for the 50 ML runoff correct?
I generally feed pH’d water every few feeds for sure. I have zero reasoning other than like yours, being to mitigate potential nutrient overload. I also feed about half strength nutes almost all the time. We have to remember that they want you to use more so you’ll buy more
I also feed/water from bottom and only really water from the top during the last two weeks or so during the true pre-harvest flush.
Hey Dan! Thanks for the invite! I’m loving it here already!!
You touched on an interesting point. You said you feed from the bottom and only really water from the top. What do you mean by that? Also, GREAT point about running the nutes lighter than suggested. I learned that about a year ago. My girls are just as happy!
Most of us grow in planters with drain holes & therefore we have drain trays. To water, I fill the drain trays & wait for the plant to pull it up. “The farmer’s eye fattens the cow” so I watch & if she drinks super quick then I know to add more etc.
I’ve done both–water from bottom & from top. I began doing only from bottom out of necessity this summer after buying some organic soil with fungus in it. Within 2 weeks the gnats were up my nose & all around. To kill the fungus gnats you starve them. To starve them you starve the fungus. That requires no water in most of that soil or grow medium.
Within about 2 weeks of doing this, I saw no more fungus gnats so I know that their food is depleted.
Also, When you transplant you can see how the roots always grow to the exterior of the pot & begin almost to form an outer shell of rootage. After seeing that along with how quickly that happens after re-potting, I began wondering why I was watering from top when the roots are at the bottom?
So because of this I don’t really do the PPM measuring that others do. I guess my using less nutes mitigates the need to do that so I’m ok.
One more reason to water from bottom is humidity in the tent. Wet soil or grow medium = more humidity, something I don’t want especially during bloom.
I realize now how much of what I /we do is from the standpoint of prevention.
@Dianna.Donnelly Bro! That makes SO much sense and yet I would’ve NEVER thought to do that. Lol. That’s awesome man! I’m definitely trying that. I don’t currently use drain trays as I have a drain setup in the corner of the room for water to run downhill and out of the flower room. However, I am going to buy a few and try that theory out. Did you find that watering that way used more feed or less?
Hi yes use plain water for sure regardless of medium, Super Soil, nutes, tea, use plain water.
Look at the plant and see what it needs.
Don’t feed just because.
I can’t stress how important it is to use plain water between feedings for many reasons.
Some peopl feed 1-2 times a week then rotate plain water when not feeding.
Look at the weekly picuture.
If you feed 2-3 times a week, use plain water on off days or base nutes only.
Some growers feed with compost tea then use base nutes to flush.
If you make full compost tea, the next feeding or later that day water in base nutes or plain water to flush. Promote runoff. That is your flush!
When you use plain water or base nutes, aim for 10- 20% to run out the bottom.
If your plants are sitting in saucers and can’t be flushed, that is a major problem!
Roots excrete latic acid from working hard, and we suggest 10-20% runoff when flushing to get the waste out the medium and roots and salt build up.
Since my soil pH is mid 5’s. I can use alkaline tap water 7.4-7.8 and it don’t matter.
I don’t pH plain water at all cause my medium controls
it.
Kyle M
Great info, Kyle! Thanks for that! So a little bit more about my feeding schedule. I may have misinformed everyone. I meant to say I feed 3 times a week. Meaning that’s all I do. I don’t flush with plain water on off days or anything. Just 3 feeds per week. However, when I do feed I make sure there is runoff each time. Should I be watering with plain water on off days too?? The soil seems to be super moist the day after and I feel like flushing with plain water the next day would really overdue it. However if I’m feeding less on the watering days then a flush on the off day’s may work. What ever is more optimal for the plants intake I’m down for trying. Thanks again!!
If you water 3 times a week, use plain water 1 if those times.
For example;
On Mon feed KTL Compost Tea.
On Weds, water in just base nutes with runoff.
On Fri, water with just plain water with runoff.
Don’t water just because.
Keep it simple and just rotate plain watet and nutes.
Monitor the EC of the medium.
Check the pH of the soil medium.
Many reason to feed with plain water.
This is what makes a grower sucessful and you must figure it out. You are the farmer and must learn it.
It’s differebt for every grow, strain, and changes weekly be on the fly.
Plain water saves money in addtion. Don’t use nutes every time you water. It’s that simple.
Kyle M,
