RDWC Your help needed please...

[Wastei]

Hi Guys,

Not new to this forum in terms of reading but newly joined to post. Not a complete beginner having done a few successful rounds on NFT but recently decided to venture into DWC for a change and to try something new. Problem is i seem to be falling at the first hurdle. I'm hoping someone can maybe point out something i could be doing wrong. OR perhaps just a bullet proof method they use that i can maybe mirror for the first part.
The problem is moving the small rockwool cubes to the net pots. Ive been doing this after noticing root growth on the underside of the cube. I've put some pebbles in the bottom of the pots (inch ish) and raised the water level of the system so bubbles ar kinda on the line of the bed of pebbles. Then put the remaining pebbles around to fit. Temp around 70f, ph around 5.9, chiller keeping food around 68f, EC about 1.1 (EC according to guardian)
Even after a week or two they don't seem to carry on growing much or at all. And some just die. I'm not top feeding as i think the cubes are keeping wet and i dont want to over water either. Only a 48w T5 propagation light in there but they're only about 2 inches high so assume that's sufficient?
Any ideas?

Stop using rockwool in DWC. It's the worst medium to start seeds or clones in DWC. Sterilized jiffy/peat pucks work very well for seeds.

You got saturated rockwool cube with hydroton capsulating it with moisture. Best thing is to to run clones in straight leca/hydroton. No possibilities for a anaerobic environment and low DO that way.

 

[rkymtnman]

I’ve run a whole grow without exceeding 1 EC why waste nutes.nutes companies want you too over feed they sell more products. That’s why there charts say to feed high.

@Renfro i'm not the only one, dude.

 

[bonytang]

Stop using rockwool in DWC. It's the worst medium to start seeds or clones in DWC. Sterilized jiffy/peat pucks work very well for seeds.

You got saturated rockwool cube with hydroton capsulating it with moisture. Best thing is to to run clones in straight leca/hydroton. No possibilities for a anaerobic environment and low DO that way.

I've germed in the reservoir w/hydroton with & w/o rock wool and just don't do it that way anymore b/c they always took forever. Heatpad & rock wool for seeds is normal but will give a go with the jiffy pucks next round.

Have always wanted to take clones straight in hydroton/reservoir but thought it would just take up way too much space if you're doing more than just a couple of cuttings.. 1 cut per reservoir you'd have to have a pretty large area so little diy cloners & dome planters are pretty much the go to. Have 8 cuts in each right now. Cloner just pH water at 6 and using GH Rapid Start for the 1st time. Dome planter cuts are gonna take at least 2wks+ so 1st go on the cloner we'll see when/if they root. It's already day 4 on both set ups.

 

[MrTwarn]

I pour a 1/2-1 cup of solution over the cube/netlid about once a day until they drop.
I run Jacks 3-2-1 at full strength from day one.

Hi again - you mention half a cup a day roughly but I’m really nervous of over watering. If the cube is still damp does that mean it’s ok not to water or not necessarily? They’re certainly not soaking wet. It’s hard to gauge this one tbh. Maybe they do need watering as they need fresh food?. Not much going on still but I’ve adjusted the light as I realised it wasn’t near enough at all which wasn’t helping. Probably why they’ve stayed still all this time

 

[GBAUTO]

I've never had an issue with any pathogens forming in the cube just doing a drain-to-waste top watering.
It's sitting on a layer of hydroton in the net lid over an empty bucket.
I just dump a cup of solution over the cube each day until roots drop.
It's really simple.

 

[MrTwarn]

That’s good to hear. I was more wondering about overwatering though

 

[BurntByFire]

I run a bit of roots gold excelerater and water first week or so at low doses, let's roots take off. Water should be just below your cube. The bubbles should barely touch the cube. Top feed with syringe if needed. Soaked Rockwood will kill your seedling.
Once roots reach for the water, drop to 1/4 inch below the planting deck and ride that water level for the remainder of the grow.

EC
Week by week
Veg 1-4
Bloom 5-12

0.2

0.35

0.6

0.65

0.85

1

1.2

1.3

1.4

1.3

0.9

0.8

So 0.2 for week 1
0.35 week 2 etc

Remember this is dwc not soil.

 

[MrTwarn]

I run a bit of roots gold excelerater and water first week or so at low doses, let's roots take off. Water should be just below your cube. The bubbles should barely touch the cube. Top feed with syringe if needed. Soaked Rockwood will kill your seedling.
Once roots reach for the water, drop to 1/4 inch below the planting deck and ride that water level for the remainder of the grow.

EC
Week by week
Veg 1-4
Bloom 5-12

0.2

0.35

0.6

0.65

0.85

1

1.2

1.3

1.4

1.3

0.9

0.8

So 0.2 for week 1

0.35 week 2 etc

Remember this is dwc not soil.

Thanks that’s really helpful and will make note of that chart. I would definitely need RO to do that as I’m at 0.6 from the tap.

 

[BurntByFire]

Thanks that’s really helpful and will make note of that chart. I would definitely need RO to do that as I’m at 0.6 from the tap.

Yes absolutely RO for this formula

 

[MrTwarn]

back again! ive noticed that over the week i see the EC go down, assume because the'yre eating the food. if i top this up to keep the desired EC level i can see signs of nute burn but couldn't before. is this normal? Is it better to let the EC go down through the week and then start again with completely new water/nutrients weekly?

 

[BurntByFire]

You need to change your water weekly as that EC you're at your have no idea what the plant ate.
Changing your water resets your water balance.

But yes during the week I would keep my EC at the level it needed to be at. Almost daily I fed or every other day

 

[Wastei]

back again! ive noticed that over the week i see the EC go down, assume because the'yre eating the food. if i top this up to keep the desired EC level i can see signs of nute burn but couldn't before. is this normal? Is it better to let the EC go down through the week and then start again with completely new water/nutrients weekly?

It all depends on how much you're feeding it. I think the problem is your tap water. You could almost chew that water at 0.6 EC.

Everything over 0.2 EC is unacceptable in hydro IMO. It's very hard to get correct nutrient ratios with half of the total EC (0.6 in your case) being disturbances in the water.

 

[bonytang]

back again! ive noticed that over the week i see the EC go down, assume because the'yre eating the food. if i top this up to keep the desired EC level i can see signs of nute burn but couldn't before. is this normal? Is it better to let the EC go down through the week and then start again with completely new water/nutrients weekly?

Hey bro yes, start a new res every wk.. twice a wk in flower. If you're seeing a little burn now it's already a sign to slow down, IMO EC at this point is just not worth trying to reach. As they grow you'll know how much they want to eat & you can adjust targeted EC after they've proven to accept the gradual increase rate of your feed. My reservoirs are 5g and I'm filling it up halfway to 2.5g and my nute mix is prepped for 1g pretty much throughout entire grow, + using the same mix for topping off.

I only see nute burn now in NPK week usually around week 3 or 4 in flower as my grow style is more on the cautious side when it comes to feeding. Try to look at it like - a lot more has been done with less - so if you can run your plants low EC/feed in veg & work them up to normal feed + additives in bloom phase, they'll be more likely to accept an EC rate you're trying to achieve vs now in early grow stage.