Is Dry Back in coco really that damn important?

Hollatchaboy

Hollatchaboy

Well-Known Member
inth3shadowz said:
I bought these plant caddys off Amazon that have water catcher trays at the bottom. I water, smoke a Doobie for 30 min, come back and just empty the trays. Its very simple and very effective lol only downside is you can't use them if you have a low ceiling as they add a few inches to height.
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No, I mean if you bottom water, how do you get runoff?
 
curious2garden

curious2garden

Well-Known Mod
Staff member
Rurumo said:
When coco dries the EC skyrockets. If it dries a little, the EC goes up a little (and vice versa)...So some dryback won't be that noticeable. I've been experimenting with this by using 1.5 g, 2 g, and 3 g pots all fed twice per day. The smaller pots get substantially more "dryback" but it's still not enough to derail them...however, they yield less than the bigger pots, simply because the larger root balls are exposed to a more idea concentration of nutrients at the root zone for longer AND also a bigger root ball means more surface area exposed to and collecting nutrients. The whole point of multifeeding in coco is to constantly refresh the nutrient levels at the root/soil interface.

Another factor is the EC you start with. If you run "low ec" (around 1) then you might not notice much tip burn or other leaf issues as you would if you run a "high EC" because the peak EC will be lower if it starts lower to begin with. This is why you can get away with pretty much as much dryback as you want with seedlings being fed very low ECs-letting the pots get light and even visibly dry, doesn't really hurt them because the peak ec at dryback never gets too high, and a wet/dry cycle helps fill the roots out.

As for what is ideal, studies have shown about a 20% increase in yield when going from 2 fertigations per day to 5 fertigations per day. So setting up an automated system and keeping that fully rooted media fertigated 5 times per day does increase yield by keeping an optimum concentration of nutrients in the root zone at all times, BUT...it's 20%. For a commercial grower, it's a nonstarter, I would absolutely keep the media more moist with multifeeds 20% is huge commercially...but at home, I'm happy with 2 feeds per day for plants that have filled out their containers with roots. I never multifeed until a transplant has a full root ball.

Keep in mind fiber length of the coco you use too. Fine fiber coco holds much more water (and much less air) than longer fiber lengths. Fine fiber coco is manufactured to mimic peat much more closely. I see new growers have trouble with seedlings all the time in coco, and it's usually down to overwatering in fine fibered coco. Of course, any difference in how you treat a plant based on the fiber length of your coco disappears once the roots fill out. Perlite makes zero difference if your coco is medium to long fiber already, and with short fiber you could add some perlite and lower it's ability to retain water....but why not just buy different coco in that case or simply make watering adjustments until the root ball forms? Any coco is easy to adjust to once you know it's characteristics.
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Thank you!! You did it for me ;) I saw this and decided I wasn't going to come tell them the salts dried out and burned the plants until after the T'giving holiday that I always drag out until the Monday after the holiday. But now I come back and see you've answered it perfectly! So now I'm thankful to you for extending my Thanksgiving ;)
 
Rurumo

Rurumo

Well-Known Member
curious2garden said:
Thank you!! You did it for me ;) I saw this and decided I wasn't going to come tell them the salts dried out and burned the plants until after the T'giving holiday that I always drag out until the Monday after the holiday. But now I come back and see you've answered it perfectly! So now I'm thankful to you for extending my Thanksgiving ;)
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awww, you made my morning!
 
I

inth3shadowz

Well-Known Member
Hollatchaboy said:
How do you keep nutes from accumulating in the coco?
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The plant just slowly uses the nute water and drinks what it needs. The whole idea that Coco has to be "replenished" or have water poured through it to feed with nutes is a lie. What I did was transplant from solo cup into the sip, and top feed maybe 2-3 times until the roots hit the reservoir, then after that it's just purely fill the reservoir no need to top water.
 
curious2garden

curious2garden

Well-Known Mod
Staff member
inth3shadowz said:
The plant just slowly uses the nute water and drinks what it needs. The whole idea that Coco has to be "replenished" or have water poured through it to feed with nutes is a lie. What I did was transplant from solo cup into the sip, and top feed maybe 2-3 times until the roots hit the reservoir, then after that it's just purely fill the reservoir no need to top water.
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That's because you aren't actually growing in coco. You're using the substrate to hold the plant up, similar to how I used netpots and Hydroton in NFT while the plant fed from the bottom of the rail or in your case SIP. Essentially as soon as the plant's roots hit the bottom I pulled the top feed lines. You sort of removed the coco from the system of irrigation. My rail's produced terrific plants the only problem was they weren't at all mobile once large whereas with individual pots I can move them, nice.
 
I

inth3shadowz

Well-Known Member
curious2garden said:
That's because you aren't actually growing in coco. You're using the substrate to hold the plant up, similar to how I used netpots and Hydroton in NFT while the plant fed from the bottom of the rail or in your case SIP. Essentially as soon as the plant's roots hit the bottom I pulled the top feed lines. You sort of removed the coco from the system of irrigation. My rail's produced terrific plants the only problem was they weren't at all mobile once large whereas with individual pots I can move them, nice.
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I can move this plant anywhere, that's the beauty about the 5 gallon bucket SIP insert. Its actually only about 4 gal of medium roughly. 1 gal ish reservoir. I wouldn't exactly say the Coco is out of the picture though, the Coco is just sucking up the water inside the reservoir to keep it moist, it's not actually just sitting in the water only.
 
Hollatchaboy

Hollatchaboy

Well-Known Member
curious2garden said:
That's because you aren't actually growing in coco. You're using the substrate to hold the plant up, similar to how I used netpots and Hydroton in NFT while the plant fed from the bottom of the rail or in your case SIP. Essentially as soon as the plant's roots hit the bottom I pulled the top feed lines. You sort of removed the coco from the system of irrigation. My rail's produced terrific plants the only problem was they weren't at all mobile once large whereas with individual pots I can move them, nice.
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Makes sense, but wouldn't he still need a way to remove unused nutes?
 
X

XYZVector

Member
I don't know starting to experiment with this technique. My issue is that my best plants tend to get the powdery mildew. I was advised by a consultant that this was caused by my night time VPD being too low. After two times of this happening, I hired a different consultant. Low and behold second consultant said this was being caused by my coco staying constantly saturated. I would fight off fungus gnats, powdery mildew. My coco looked like it was saturated in fungus, and algee. I am allowing drybacks, but this technique requires special hardware to get it right. You have to be able to monitor the root zone pore EC, and the water content of the root zone with precision. Otherwise you can go to far, and dry out your coco completly, and destroy the plants. Don't get me wrong this system still waters until 10% runoff, it just does it once or twice a day in flower. So the runoff ec is staying at a correct level. It is just that it will not constantly water the plants to keep the ec at the correct level. When it decides to water it does it in shots of water, it will give 3-5% of the container volume per event. Then it will wait 15 minutes to see if any runoff occurs. This is repeated until there is runoff, once done it will stop watering the plants until a sufficent dry back of 20%-30% occurs. Then another water cycle will occur, my runoff is consistent, and it always ends up at about +100 uS of the inflow ec. I have noticed my plants are growing at explosive rates. There are other factors at play also like the VPD, and ec of the inflow water. I like to keep my inflow low, around 1050-1150 uS. First this gets rid of the fungus, and gnats, and second I noticed the plants are searching for water and filling out my coco with dense roots instead of just occupying the upper half of the air pot.
 
B1unt_UK

B1unt_UK

Member
For what it’s worth I find drybacks in the first few weeks very beneficial for root growth…

When they’re small I find saturating the coco stunts root growth, when the media starts to dry out the roots hunt for water, colonise the container & the plant grows faster (seems to be popular starting auto’s in their final container, flooding them & getting an 18” tall plant).

You don’t need fancy kit, just lift the pot to see how heavy / saturated it is. If it still has weight to it, keep an eye on it until it’s lighter & water then.

Same deal when transplanting, water in to a bigger pot & more coco, leave it to dry out a little & then water again.

It’ll start something like every few days, then every 2 days & when it needs watering daily then you can then keep the coco more saturated, knowing the plant can handle the volume (based on what it’s drinking).
 
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