First Grow - DWC 300W LED - Northern Lights Auto - 3 Plants

Introduction

Why hello there! After many hours, days and weeks reading posts; absorbing all there is to know about growing - I have begun my first grow! It's been such a help reading journals from a spectrum of beginner to advanced growers that I felt it was my turn to offer something back; as well as hopefully gaining further advice from all you lovely fellow stoners


My Setup
Tent: DS60 (2ft x 2ft) x H(5ft)
Light: Galaxyhydro 300W (output) LED - (draws 145W)
Ventilation: 105m^3 /hr extractor fan pulling through a Rhino carbon filter, passive intake
Reservoir: 42 litre DWC (with 6 airstones connected to 30lpm air pump) - can hold up to 5 plants
Grow medium: Hydroponic, mix of clay pebbles and coco coir
Nutrients: Canna aqua range for hard water (with cannazym, rhizotonic, pk13/14 and boost)

Other: Desktop fan




Note: This photo shows my original air pump, this was later replaced with a more powerful one


Germination
To begin with I germinated the seeds for 24hours in tap water - the water here is quite hard; coming out the tap at a slightly alkali 280ppm. I boiled a glass of water, allowed it to cool to room temperature and popped in 4 auto feminised northern lights seeds from Sensi. A day later tap roots had begun to emerge and they were transplanted into Root Riot germination plugs and put into a propagator at 18-23*C with the lid on to keep things lovely and humid.






Two days later and I had my first sprout, the next day another followed and then the third came out an additional 3 days later. Unfortunately the last didn't make it - and I have to say, it was completely my own doing. Anxious for it to sprout and curious as to how the root was growing - I often would have a VERY careful poke around to see how things were progressing. Despite this stress it did look like it was starting to sprout! But like a beginner on a killing mission I tried to help him along by gently removing the seed casing (prematurely!) and condemning him to death. RIP #4. Looks like curiosity doesn't just kill cats.



None the less, 3 little sprouts survived and were ready to face the onslaught of inevitable mistakes that my first grow would throw at them.









Day 1
So here is where the biggest (possibly the most common?) beginner mistake was made. Day 1 was the day I added nutrients.


As soon as the sprouts came up I put them under the LED light in their net pots with a coco coir and clay pebble mix, the reservoir had pH balanced (5.5) tap water (ppm 280) that had been left to sit for 24hours to dechlorinate. This was still Day 0, when the first actual leaves (not the cotyledons) began to show, I called this Day 1 and added nutrients.


Note: the hardness of my water is due to an abundance of chalk in the local area.



I added all my nutrients and my PPM sat at 840 - I know all the experienced growers are recoiling at the thought of these seedlings being intoxicated with that much - but my naivety meant that I thought they'd be fine and I could just add more water later to get the balance right, I was wrong....


Day 10

Things look fine, all 3 of my plants are doing about the same.



Day 15
My plants are showing clear signs of nutrient burn (sorry I don't have a photo) - I change the reservoir at this point and refill with pH balanced water. However I keep in a few litres of the old reservoir so the plants have a small amount of nutrients. Total ppm: 337 (barely above my water's natural ppm)


Day 18
End of my 3 day flush (was this too short?) - I added nutrients to bring ppm up to 595, pH 5.6


Day 22
Here you can see just how bad the nutrient burn was:



You'll also notice a wooden cover on my black plastic reservoir, this is because it was absorbing too much heat (often the water was about 23*C with lights on), I made the wooden top and covered the sides with reflective insulation: My average conditions are now:


Humidity: 40-60%

Air temperature: 21-23*C (lights off), 25-30*C (lights on)

Water temperature: 20*C
Light: 18hrs on, 6hrs off.



It is worth noting (using hindsight) that given the level of nutrient burn my ppm is still running high and for the next few weeks I simply top up with water and pH balance. From the above photo you can see that the plant on the left was most affected by the burn:





and the plant on the right least affected:





The stunted growth of those more affected remains prevalent as the grow continues.....


Day 28
Recovered from the burn they are starting to flourish, new growth is burn-free.



Close-up of largest plant:



Day 31





And here we are at present day. Today I noticed my smallest and largest plants (not my middle one though!) have entered the pre-flowering stage from the evidence of calyxes:



Summary (so far)

Other than my enthusiasm on the nutrients at the start, things seem to be going well for a first grow. In the past week my plants have seen a lot of growth. I've only changed the reservoir once so far after 30 days. I plan on another change as I switch over to flowering nutrients, which leads onto a few questions I hope can be answered:




I've just seen evidence of pre-flowering (2 calyxes protruding from nodes) on 2/3 of my plants, when would be the right time to switch to flowering nutrients? (bearing in mind all 3 plants share the same reservoir)



How do you think my plants are doing in terms of size and health for 4 weeks in?
(I'm looking to gauge just how bad the nutrient burn stunted growth)


Based on the above is there anything you can suggest to improve my grow?



<span class="redactor-invisible-space">All feedback welcomed. </span>Thanks

 

Ha, it looks clear from the photo! - but it's just camera trickery with reflections, it's actually a black container and completely opaque, no light getting in there but I have a lot of airstones just to make sure the roots keep healthy - and I shared your concern so took a peek at roots today, doesn't look like any problems, all I can desribe them as is white and... everywhere lol