When to begin nutes in rdwc

rkymtnman said:

could you post up what your nutrients and amounts are ?

were you the one that was using Lucas formula? or was that another grower?

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Absolutely! I'm not doing water changes so it's difficult to provide an exact number for nutes considering some of the tds is calimagic and I'm unable to judge how much of that has been consumed.
Nutes were adjusted to 450ppm approximately a week and a half ago and calimagic was assumed to be around 200 after increasing it. Those numbers aren't exact as I'm not sure how much of either was consumed prior to testing the tds and increasing both. The tds was 592 when I checked it yesterday, down from a combined 650 when i increased both. The tds drop stops or slows way down for the first day or two after adding shock.
No I'm not using the Lucas formula. I'm the one who asked about brown spots on the plants a few weeks ago, asked you how to use shock.
I attached a couple pics of a plant incase it helps determine what nutrient concentration I should be shooting for.

rkymtnman said:

were you the one that was using Lucas formula? or was that another grower?

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Come to think of it, I may have inquired about the lucas formula a while back. Its something I've been considering since day one when I decided to skip water changes. Is it too early to start the lucas formula? Would those concentrations cause nute burn at this stage of veg? Im down to do a full water change and switch to lucas if the timing is right. I would prefer to switch. And any advice or guidance you could share regarding when and how to start lucas would be greatly appreciated!

if you zoom in on that first pic, you can see tip burn on the new leaves. the good part is that the ppms drop daily.

alot of people dont' do res changes but i was always of the mindset that a total change after 10 days was best to keeps the nutes in balance. if you only do top offs, you have no idea (exactly like you said) of what nutes are left

and for your lucas question, the only important thing is the 1:2 ratio micro/bloom

i start off with 1mL/2mL for seedlings and then slowly increase. 8/16 is the actual ratio but i never could get higher than 4/8 or 5/10 without tip burn.

i rarely needed more Ca even with RO water

rkymtnman said:

if you zoom in on that first pic, you can see tip burn on the new leaves. the good part is that the ppms drop daily.

alot of people dont' do res changes but i was always of the mindset that a total change after 10 days was best to keeps the nutes in balance. if you only do top offs, you have no idea (exactly like you said) of what nutes are left

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I notice the tip burn and have been trying to research the cause. So many things resemble each other that I'm having trouble deciphering the cause. What's your conclusion. Nute burn?

My system is 20g of water total and I use ro that I make at home. The ratio of waste water to ro when making ro is like 3:1 or 4:1. Regular water changes seems incredibly wasteful, water and nute wise. That's my rational for choosing no water changes. But you made a very valid point regarding the trouble with not changing water. Now I'm questioning my method

rkymtnman said:

and for your lucas question, the only important thing is the 1:2 ratio micro/bloom

i start off with 1mL/2mL for seedlings and then slowly increase. 8/16 is the actual ratio but i never could get higher than 4/8 or 5/10 without tip burn.

i rarely needed more Ca even with RO water

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Do you think 4:8 would be a good starting point for the current stage of growth? Or should I start with like 2:4, see where that gets me ec/tds wise, and adjust based on the plants response and tds/ec consumption? Sorry for the million questions, man! Just trying to make sure I don't screw something up.

420Mn said:

The ratio of waste water to ro when making ro is like 3:1 or 4:1

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yep, i tried one unit and hated how much it wasted. water is a precious commodity in CO. so i lugged 5 gal jugs of ro from walmart for the first year or so. then i slowly transitioned to all well water.

and iif i remember, 5/10 lucas is pretty close to 1EC with ro water.

rkymtnman said:

yep, i tried one unit and hated how much it wasted. water is a precious commodity in CO. so i lugged 5 gal jugs of ro from walmart for the first year or so. then i slowly transitioned to all well water.

and iif i remember, 5/10 lucas is pretty close to 1EC with ro water.

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You have incredible timing! I was at the hardware store picking up some buckets and lids for that exact purpose when your reply came thru. There is an ro service station in the town next to me. That water comes out in the 60° range, whereas with how slow an ro system produces water, the water temp is in the low 70's by the time it's ready. The ro system is in my fish room since it's used to produce rodi water for my reef tank. That room is warmer because the reef tank runs around 78°, which warms the room up.

Do you think the tip burn is nute related? If so I assume I should shoot for slightly lower ec/tds? Or keep it in the range it's in since the tds is dropping?

420Mn said:

I notice the tip burn and have been trying to research the cause. So many things resemble each other that I'm having trouble deciphering the cause. What's your conclusion. Nute burn?

My system is 20g of water total and I use ro that I make at home. The ratio of waste water to ro when making ro is like 3:1 or 4:1. Regular water changes seems incredibly wasteful, water and nute wise. That's my rational for choosing no water changes. But you made a very valid point regarding the trouble with not changing water. Now I'm questioning my method

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A permeate pump can increase an RO's efficiecy, increase production and reduce waste.

1212ham said:

A permeate pump can increase an RO's efficiecy, increase production and reduce waste.

Amazon.com

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I do have a booster pump running but it's a 75gpd system that takes about and hour and 40 minutes to make 5g.

rkymtnman said:

when i did dwc, i liked letting it get up to 6.3 and then adjust down to 5.5 and let it climb to 6.3 again

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This is good advice right there @420Mn! Not sure where you are getting the idea that the pH should be higher but for hydro Ca is best absorbed from around 5.0 - 5.8 so if you are staying higher than that you could be starving them for Ca and tossing in more CalMag won't help. Different for soil when the pH should be higher for Ca.

Absorption doesn't end or begin at such definite points like the chart suggests but will taper off at the ends. This is why fluctuating pH levels are good for the plants as they get to spend some time in each nutrient's sweet spot and gobble up what they may be lacking at different pH levels.

OldMedUser said:

This is good advice right there @420Mn! Not sure where you are getting the idea that the pH should be higher but for hydro Ca is best absorbed from around 5.0 - 5.8 so if you are staying higher than that you could be starving them for Ca and tossing in more CalMag won't help. Different for soil when the pH should be higher for Ca.

Absorption doesn't end or begin at such definite points like the chart suggests but will taper off at the ends. This is why fluctuating pH levels are good for the plants as they get to spend some time in each nutrient's sweet spot and gobble up what they may be lacking at different pH levels.

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Thank you! I was obviously looking at a bad chart. What you are saying makes complete sense. I am starving them of calcium by keeping the ph around 6.0-6.1. I kinda suck at this hydro stuff lol

OldMedUser said:

This is good advice right there @420Mn! Not sure where you are getting the idea that the pH should be higher but for hydro Ca is best absorbed from around 5.0 - 5.8 so if you are staying higher than that you could be starving them for Ca and tossing in more CalMag won't help. Different for soil when the pH should be higher for Ca.

Absorption doesn't end or begin at such definite points like the chart suggests but will taper off at the ends. This is why fluctuating pH levels are good for the plants as they get to spend some time in each nutrient's sweet spot and gobble up what they may be lacking at different pH levels.

View attachment 5327511

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Can I bring it down to 5.5 range at one time or do I need to do it slowly?

420Mn said:

Can I bring it down to 5.5 range at one time or do I need to do it slowly?

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Just adjust down to that or lower as it will likely rise on it's own before long. I would often hit as low as 5.0 but by the next day would be 5.5 and rising.

I would add your pH down enough to make a difference then check in an hour then add more as needed to aim for 5.5 but don't worry if it goes a bit lower or is 5.6. Too much up and down in quick succession isn't good. A lot of people are anal about it and bounce the pH around too much. Auto pH dosers are bad for that if not set correctly.

Thank you rkymtnman, OldMedUser, and everyone else who has been investing their time and knowledge to help me thru the learning curve of understanding hydroponics. You all are fa

OldMedUser said:

Just adjust down to that or lower as it will likely rise on it's own before long. I would often hit as low as 5.0 but by the next day would be 5.5 and rising.

I would add your pH down enough to make a difference then check in an hour then add more as needed to aim for 5.5 but don't worry if it goes a bit lower or is 5.6. Too much up and down in quick succession isn't good. A lot of people are anal about it and bounce the pH around too much. Auto pH dosers are bad for that if not set correctly.

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It's a relief to know that if it drops below 5.5 it's nothing to be concerned about! Thank you for the advice to take it slow and wait an hour. That's close to what I'm doing.

420Mn said:

Absolutely! I'm not doing water changes so it's difficult to provide an exact number for nutes considering some of the tds is calimagic and I'm unable to judge how much of that has been consumed.
Nutes were adjusted to 450ppm approximately a week and a half ago and calimagic was assumed to be around 200 after increasing it. Those numbers aren't exact as I'm not sure how much of either was consumed prior to testing the tds and increasing both. The tds was 592 when I checked it yesterday, down from a combined 650 when i increased both. The tds drop stops or slows way down for the first day or two after adding shock.
No I'm not using the Lucas formula. I'm the one who asked about brown spots on the plants a few weeks ago, asked you how to use shock.
I attached a couple pics of a plant incase it helps determine what nutrient concentration I should be shooting for.

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They look good. I wouldn't add any more calmag right now. If pH is the problem they'll be able to access what is already in there. That tiny bit of tip burn isn't harmful but says your nute levels are at the top of the scale for now. They should really take off very soon so don't worry if the grow tips are lime/yellow in the centres as tehy can take a day or two to 'green up' when the plants grow rapidly. Measure them every couple days to see how they react to the lower pH but they are at that stage they should shoot up fast.

OldMedUser said:

They look good. I wouldn't add any more calmag right now. If pH is the problem they'll be able to access what is already in there. That tiny bit of tip burn isn't harmful but says your nute levels are at the top of the scale for now. They should really take off very soon so don't worry if the grow tips are lime/yellow in the centres as tehy can take a day or two to 'green up' when the plants grow rapidly. Measure them every couple days to see how they react to the lower pH but they are at that stage they should shoot up fast.

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Thanks man! I backed off the idea of upping the calmagic the moment I read your comment and viewed the graph you shared about calcium uptake and ph levels. My issue isn't a lack if calcium, it's that I've prevented the optimal uptake of available calcium by keeping ph pinned above 6.0. I believe you and rkymtnman are spot on with your diagnosis regarding the ph and the advice to drop it to 5.5 and let it rise to 6.3, then repeat.

Thanks for the info regarding the nute burn and nute level. That is very useful info to me.

Should I keep the defoliation minimal due the calcium deficiency?

420Mn said:

Should I keep the defoliation minimal due the calcium deficiency?

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You could still snip out lower nodes and take off leaves of no use. With lots of that healthy top growth getting all the light they'll do a little better with some of the basically useless stuff from down below gone. As long as that stuff is growing it's drawing on the plants resources and contributing little to nothing.

OldMedUser said:

You could still snip out lower nodes and take off leaves of no use. With lots of that healthy top growth getting all the light they'll do a little better with some of the basically useless stuff from down below gone. As long as that stuff is growing it's drawing on the plants resources and contributing little to nothing.

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I'm not sure what constitutes leaves of no use? Smaller leaves on the branches, below the top 2-3 nodes?

420Mn said:

I'm not sure what constitutes leaves of no use? Smaller leaves on the branches, below the top 2-3 nodes?

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Yeah. Ones in the lower end of the plant and in the middle down there that never get direct light on them. Be selective and don't worry too much about whether to take or leave one as it really won't make a huge difference. Cannabis is very well suited to loosing parts of itself without causing any problems. Heavy defoliation is just such a waste in my opinion as the plant just turns it's energies to making more leaves rather than growing the whole plant. I mean they're the solar panels that power the plant and mother nature wouldn't grow them if they weren't critical to the plant's health.

If the plants are low on some nutrients they pull them from the older leaves so they also act as storage for times of need so you don't want to go crazy. The nodes draw a lot of energy to grow so like I said you can just nip them out and leave the leaves on if they are getting light. Now instead of feeding that node they help feed the whole plant. The plants have a circulatory system like we do so everything is always moving to where it's needed the most. It's a whole chemistry lab in there working 24/7 to make things work.