Grow Mediums Taking the DWC plunge

[Z_Burp]

Day 35 update (sorry for the blurple pic):

Did a res change today, first one so far. I didn't really know where the nutrients were at this point so I figured it was time. Also, I bumped up the nutes.
She's still using about a gallon of solution a day. Main stalk is about as big as my thumb at the bottom. I'm very happy with DWC so far. She's MUCH bigger than my first NQ.

5.81 pH
625 ppm

 

[Raoul Duke]

Lookin real nice!

Sent from my red IBM Selectric

 

[Mañ'O'Green]

z_Bop:

I highly recommend that you change nutes every 7 days. Even if topping off is keeping you in the target PPM zone, the ALL important balance between the different salts can be way off. This can cause a lock-out situation and is very difficult to diagnose before undue stress is applied to the plant. DWC is the most difficult form of hydro and problems occur very rapidly. You need to stay ahead of the grow not chasing it.

 

[Z_Burp]

z_Bop:

I highly recommend that you change nutes every 7 days. Even if topping off is keeping you in the target PPM zone, the ALL important balance between the different salts can be way off. This can cause a lock-out situation and is very difficult to diagnose before undue stress is applied to the plant. DWC is the most difficult form of hydro and problems occur very rapidly. You need to stay ahead of the grow not chasing it.

Done and done
Thanks for the advice! I did originally plan to do that, then I read about other people who didn't. The lure of less work got the better of me.

So, new plan:
Res change every week

Should I top off in between reservoir changes with just pH'd water, or some percentage of solution that was just mixed? I've read it being done both ways.

Thanks again

 

[Mañ'O'Green]

Keep the water level constant at 1/2 to 1 inch below the bottom of the net pot at all times. So top off at least daily or more often if you can. Then two weeks before harvest let the level drop slowly to about 4 or 5 inches below the bottom of the net pot. This simulates drought and mildly stresses the plant to reproduce before it "dies" for lack of water.

I use 20% to 30% strength of the nutes I started with in the bucket: so if starting 800 PPMs then 160 to 240 PPMs for the top off solution. It just depends on how much water/nutes the plants are taking up. The idea here is to keep the nutrient strength the same as what you started with all week. It is pretty easy to keep the nutrient strength consistent but impossible to know what the salt balance is without expensive lab equipment. The plant may use more or less of something throwing the solution out of balance. I didn't invent this stuff I learned it somewhere. This is taken from a Dyna-Gro information sheet:

Leibig’s Law of the Minimum:

Many growers have learned that there is more to plant nutrition than NPK. Justus von Leibig formulated "Leibig's Law of the Minimum" in the 1840s. He showed that plant growth is always limited by the lowest level of each essential mineral element. This concept is often illustrated by a barrel with staves of different lengths, each of which represents an essential mineral element. You can only fill the barrel to the level of the lowest stave. By analogy, a plant can only use nitrogen, for example, to the extent of the lowest level of each other essential mineral element. Feeding at 200 ppm N with a fertilizer that contains no calcium, magnesium or sulfur (all macronutrients) means that most of the NPK cannot be used by the plant.This is why we change out the solution every 7 days then we are assured of a proper balance.

I hope this helps you understand why I do what I do!

 

[Z_Burp]

Great illustration. That brings things into perspective.

 

[Z_Burp]

Possible deficiency pics day 36, 6/24/17:

Lower leaf

Upper leaf

pH - meter calibrated weekly

Reservoir change nutrients
CM - CaliMagic, KB - Kool Bloom

Hopefully my writing is legible. I keep pretty good track of what's going on.
I can't figure out what this might be. I already looked through the "Self Diagnose Your Own Plant" thread but I can't locate a similar looking deficiency. Maybe my nutrient numbers will help on the last picture.

Doesn't look like a big deal currently, but I like to keep my eyes on her!

Thanks!

 

[Mañ'O'Green]

78°F reservoir temperature begs the question are you running Botanicare HydroGuard? If not you should.

Looks like a little calcium deficiency due to the previous reservoir change schedule. That is fixed now. You may want to add a little cal-mag. Other things can also damage leaves. Do you foliar feed? if you do it could be light burns?
Keep us posted.

 

[Z_Burp]

78°F reservoir temperature begs the question are you running Botanicare HydroGuard? If not you should.

Looks like a little calcium deficiency due to the previous reservoir change schedule. That is fixed now. You may want to add a little cal-mag. Other things can also damage leaves. Do you foliar feed? if you do it could be light burns?
Keep us posted.

Yes. I'm using Botanicare Hydroguard according to the label.

I thought it was calcium deficiency, also. I just wasn't sure because it looks different somehow. Bigger spots, I think. I'll add a bit more Cal-mag.

I do not foliar feed. I'm not that advanced yet for my personal growing.

Thanks for the feedback @Mañ'O'Green!

Edit: I've mixed up 5 gallons of 25% strength solution and am topping off daily+

 

[Mañ'O'Green]

Be sure to aerate your top off solution and check/correct the PH daily as the aeration will release calcium ions raising it.

I swear by HydroGuard in a warm (hot in my summer grows 88°F) DWC reservoir. I never got root rot when using it.

This girl is going to reward you handsomely for your hard work.