Santanesia in drain-to-waste using 12/12 system under 400W Cree COBs

My first grow journal here. Hope people will enjoy and/or can give me good tips

I'm growing Santanesia which is a cross of PH Amnesia x Santa Maria F8. I did one run before with these seeds and I got some excellent results.

The plants will be grown This time I'm going to use the 12/12 system This means that the seeds are already started under 12/12 light there is no real veg period. Although it generally will take 4 weeks for the seedlings to start flowering.

Advantages would be that the grow goes faster, plants stay smaller and there should be less manicuring since the plants tend to just grow one big bud mostly. I'm not sure how well this strain is suited for 12/12 but I guess we'll find out. Last run I did with this strain some plants gave me nice long cola's which looked to me like a perfect fit for the 12/12 system:

that's not me in the picture

Disadvantage is that you need to grow a lot more plants to fill the space. About 25 per square meter would be needed. In this case I'm using regular seeds to I started with about 40 seedlings.


There are 10 more to the left (not in the picture)

It did struggle a bit to keep the perlite watered properly. Guess I should have used bigger pots or submerged the pots a bit.

10 days later these were transplanted to bigger pots (19.5cm 6.5l / 7.7" 1.7gallon):


10 days later again. After removing the males and some freaks, I'm left with 23 plants which should suffice for my 100x100 (3.3' x 3.3') tent:


The plants are picking up the pace in growth and the leaves are getting a bit pale, so I will increase the nutrients a bit.

Plants are growing in a drain-to-waste system using pots filled with perlite. The drain runs off the table into a gutter. I'm still working on automating a top-drip system to keep the perlite watered.

I'm already using an Arduino/Raspberry pi system to monitor the grow:

The chat above is not from the current grow, but I monitor ambient temperature and humidity in and outside of the tent, root temprature and plant temperature. The plant temperature is used together with ambient temperature and humidity to calculate the VPD (orange line) which should normally be in the green band.

The light used is a DIY COB light using 8 Cree CXB3070 AB COBs using 400W in total.

One week of flowering has passed so time for an update.

I have raised the EC to 2.0. The drain is between 1.75 and 1.85.

The tent is filling up nicely. I have sorted the plants a bit to size, with the longest ones in the back.


I have a removed three more plants since last week. It was getting a bit too crowded and thse three were a bit behind on the rest.
Now there are 4 rows of 5 plants. I removed some plants from the middle to show the placement:


The picture is a bit fuzzy, but it's still visible that the stretchy pheno's are in the back and the more bushy plants are in the front.

What's funny is that the stretchy plants were the first to flower, but in a previous grow I found that this stretchy pheno had the longest flowering time. So not only do they start flowering earliest, but they seem to go on longer too. This pheno is what produced the large cola's in the previous post.

The plants are on a sloped table where the water drains into a gutter in the front. The slope is about 1cm per meter (1/4" per yard), but I think I should have gone a bit steeper to make sure the water drains more completely. A lot of water remains and evaporates which raises the humidity quite a lot.

The tops are'n much yet, but it's coming



Some of the stretchy plants show some claw. I had the same in a previous grow. Not sure what to do here since some of the other plants are a bit pale. They all get the same water, so I have to compromise a little.

I'm still working on automatically watering the plants. I received parts for it, but I'm still testing an trying some things out. I guess I should just install something and see how it works. I'm mostly worried if the pump I have can deal with the sprinklers. It's a circulation pump from a DWC undercurrent system and not designed for high pressure application pushing water through sprinklers/drippers.

Another week has passed, so time for an update. Two weeks of flowering have passed.

It's getting a bit too full. The guide for 12/12 system claims between 23 and 26 plants should be used with a 400W light and 30 to 35 under 600W (HPS in both cases).

So I opted for 25 in a 100x100 tent (3.5'x3.5'). I reduced that already to 20, but I feel 16 would probably fit better still. Yet I feel reluctant to kill four mote plants.

The plants have not been topped or trained (besides two plants that really got too high), so I'm depending on the main cola's. Which is actually one of the major points of the 12/12 system. This style of growing should produce one cola per plant which is easy to manicure. With much less branching than you would get with a veg phase.

So the plants are a bit more open in structure than when I grew these last time with a veg phase. There is no closed canopy blocking off all the light to lower parts. Still I think 16 would have been a better number to aim for. If I ever do this 12/12 system again I will go for 16 instead of 25.

I'm also not cleaning the underside of the plants. I'm going to let them grow out to see how everything develops.

I lowered the EC to 1.9, because the drain was getting higher than what I was feeding. I can probably still go a bit lower. Also to stop the "claw", which some plants show, from getting worse.

Overview of the whole field of 20 plants:

The tallest plants are in the back (tallest is 93cm = 36.6"):


In the front are the shortest ones (on a riser to sort of equalise the height). Shortest is 60cm (24"):


I took one plant out and took a picture with a flash to get a better indication of the color. This one is 70cm (27.5")


I have installed a first prototype of an irrigation system. I still need to make something to attach the sprinklers to the pots. The 3D printer will be used for making those parts. For now just tying them together seems to work fine too. This is a lot less work than hand watering them twice per day:


The tops are developing nicely:


Still a lot of things to improve before I have the perlite buckets working the way I like (after switching to this from DWC), but it's going reasonably well for now. I think

12/12 and getting so tall... nice growing so far

Curious how much Bud each plant produces to be honest have not seen a sea of green in years and years

looking good !

Yeah, they are getting a bit taller than I expected.

Update time, the ladies have had 3 weeks of "visible flowering" and it's all going smoothly I guess. Bit crowded, but I'm not going to remove any plants now.

The light is at the highest it can go, so I do hope they stop going up. I can lower the drain table a bit, but I 'd rather do that in between grows. I left some extra space so I could experiment with irrigation solutions until I figure out what works best. Still haven;t gotten there though.

Also trying to find the right EC for this strain on this drain-to-waste system. Before I had to increase the EC when they were going yellow, but now the EC of the drain was going up. I flushed them back to 1.3 and will start from there.

Overview of the "sea of green":


Photo's of some of the tops:

This one is already starting to get orange pistils. Previous grow I also had some phenos that took 6 weeks and others would need 10 weeks. It's still a matter of testing this seed batch hoping some nice comes out for use as a mother plant.

Time for another update after 4 weeks of flowering

It's all just going smoothly I think. Growth has ended, so now its just a matter of waiting for the tops to develop and finish. In some places the first oranje pistils are visible. Some tops are already covered in orange pistils. There are some big differences in flowering duration with these seeds. I knew that already up front, but I'm testing and trying to find a special one

Trying to find the correct EC though. Growing this way in pots filled with perlite is new to me. I'm checking the drain trying to keep that somewhat stable.

This tent is in an attic room ands it's getting quite warm there, but the temeratur in the tent is reasonable at 29C (84F). The air is reasonably humid (60%) so that probably helpst the plants cope better.


Then some pictures. First an overview of the bunch:


A top from a bit more up close:


Assortment of other tops:

Update after 5 weeks of flowering.

It's still going well. No issues really. Just trying to get the hang of EC in this method. I have lowered the EC to 1.3 and I think that's still a bit high. Also contemplating on recirculating for a day and then doing a daily res change. As a halfway between drain-to-waste and DWC. Recirculating would make it easier to control the EC and pH in the pots.

It's quite a wide variety of different pheno types and some need more nutrients than others. The "lean" ladies are getting some buildup of nutrients in their pots even though I drain quite a lot. Recirculating for a day would help get rid of the buildup. Daily res change would still keep it fresh every day.

Anyways, time for pictures

I needed to take the filter out of the tent since the drain table and high pots and some tall plants meant I had no vertical space left. Unfortunately I couldn't find the correct size coupling attaching the filter to the outside of the air vent. So I 3D printed a part (in pink):


Overview:


A selection of tops:










A few tops look almost ready to harvest (the two plants next to the sensor in the middle of the third column from the left). I will take some macro pictures to check the trichomes.

looks nice sofar. keep it up!
may I ask what you used as a drain table? Or did you build one yourself..

Thanks. I built the drain table myself. It's made from 5cm (2") beams with plywood on top and an edge of plywood covered by pond liner. The gutter in front catches the drain and directs it to a reservoir where it gets pumped out.

Thinking about recirculating the drain though. I find it really difficult to keep the nutrient levels steady with all these different pheno types using drain-to-waste. Some plants need a lot more nutrients than others. The ones that don't eat much end up with rising nutrient levels in their pots and the ones that do eat show a declining EC/TDS.

I flush it a lot now once a week to get it back level, but simply recirculating the water would likely make the EC in each pot much more stable. Much like I was used to in DWC.

Took some pictures of a few tops with a macro lens. The first amber trichomes are visible, so I like to check them with macro photo's.

This is one of two plants that seems almost finished to me:


plus a 100% crop:


This one needs a bit longer still:


plus another 100% crop:


and this one has barely an orange pistil yet:

6 weeks of flowering done. I will check the trichomes again later. Probably the two earlier plants can be taken out.

The rest is also starting to get more and more orange pistils.

I have definitely changed from drain-to-waste to recirculating. Flushing the pot thoroughly keeps the EC and pH much more stable. I guess when growing cuttings, drain-to-waste would work, but with all these pheno's (and their varying nutrient uptakes) it was just not happening.

With the lights lifted up, there is a lot of shadowing so I added some flash here and there. The combination of warm white leds and flash gives it the yellow+blueish hue here and there.

On other occasions I use softbox flash lights, but I couldn't get them this time.

Anyway, lets see some photo's.

Overview:


Some photo's of tops:

Man that looks really good! I'm probably not telling you anything you don't already have your eye's on but with how your temps and humidity are going I'd be on the lookout for bud rot. Looking tasty though

What have they been? RH AndTemp

thccbdhealth said:

What have they been? RH AndTemp

Click to expand...

Post #8

wietefras said:

This tent is in an attic room ands it's getting quite warm there, but the temeratur in the tent is reasonable at 29C (84F). The air is reasonably humid (60%) so that probably helpst the plants cope better.

Click to expand...

My over night highs are 56-57%RH
daytime is around 45
The memory function sometimes shows a low of 35.

@Green_Skunk, @thccbdhealth

Yeah I know. The tops aren't very fat though so I'm hoping they will be OK again. Previous time I grew this strain I had no rot either.

Trouble is that outdoors (and at the intake) the relative humidity is around 60%. I'd have to run a humidifier all the time to try and get things under control.

Plant Temperature (green line) and therefore VPD (orange) are unreliable because the canopy is rather open and temperatures range from 26 up top to 20 degrees deeper down in on the plants. Well I guess it's a fair average, but I mean the VPD up top and and down inside the crop are miles apart.

The gap between the yellow (top temp) and purple (in the middle of vegetation) temperatures are also wider than I've ever seen. I guess I should try to fix that with better air circulation. Probably the big drain table in the middle of the tent is blocking the airflow through the crop restricting it to more along the walls. Something to improve for next grow.

Or perhaps I should reverse the circulation again. With COBs/leds the issue is more getting heat into the vegetation rather than getting it out of the tent. I usually hook the exhaust fan up to the bottom of the tent to force the warm air through the vegetation. I switched it around recently because it was getting too hot, but now it's cooler again and then the temperature down in the tent gets too low for my liking.

I'm just jumping in because I want to follow the rest of your grow. I don't have any valuable input other than the fact I'm blown away at how meticulous you are with your grow (if you consider a fan valuable).

Im finding myself reading the thread over, just so I can gather some understanding of how you're monitoring everything. It's so very thorough.

3D printing? You're taking this to new levels.

Ha thanks. Always nice to hear people enjoy reading/watching something too

In my signature is a link to a thread with some Arduino projects showing how I measure and log things.

Well I found the first bit of rot already. In the top seen in the left front of the overview photo and also on the third photo I was keeping an eye on that top because it has that build that looks most suited for rot. Nothing to see in that photo I think, but two or three days later and I noticed some sudden yellowing in a fan leaf. So I opened it up and indeed there was a start of some rot inside.

It's still raining a lot over here, and intake RH remains around 65%.