Sour Diesel and Grapefruit, first tent grow
I've been growing in coir for years in our cold climate, doing 6-12 plants, seedlings and veg indoors with admittedly not enough light, then after the flip moving to a greenhouse and finally outside in full sun once it warms up enough. I've been getting decent yields but not great. I finally decided to switch to a tent this year, so I can get in two smaller crops a year.
Pre-tent (Sprout-Seedling) 15W then 45W blurple LEDs
Tent: Mars-Hydro 120x60x180cm tent, Mars-Hydro SP250 LED light. Oil heater and fan in tent to keep the air moving around. I have some containers of water between the heater and plants to try to raise the RH. Using Coco/Perlite, General Hydroponics nutes, and trying Dr. Coco's schedule this year. Using LBH's 4-way LST and SCROG to maximize yield of three plants (2 Sour Diesel and a week or so behind, one Grapefruit).
Started 3 sour diesel, 1 white widow, 1 super lemon haze (all from 2019 leftover seeds). Also started 1 big bud, 1 grapefruit, 1 green crack (2020 seeds). Roughened seeds with the tube of sandpaper trick on 4/4 and started soaking in distilled on warming pad at 30°C. Moved to paper towel after 3 hours. Everything started great!
36 hours later (4/5), the GF and GC had 1-cm long radicles, and I planted them in coir under a humidity dome under a dark towel. By the next day, the SD were at the same point, and I planted them as well. A day later (4/7), the SD, GF and GC had their heads above the soil, so I put them under a low-wattage LED, and kept their helmet heads moist with warm distilled water until they fell off. By the evening, the cotyledons were starting to photosynthesize.
Then things went bad. The BB and SLH seeds split, but never grew radicles. The WW seed grew a radicle, but after planting, never grew above the soil. One of the SD and the GC and GF seedlings died. I started soaking 2 more Big Bud and 2 more Grapefruit, the last of my seeds for this year. Actually, it turned into 2 BB and 1 GF, when one of the GF seeds mysteriously disappeared from the soaking dish on the way to the grow room. Note to self: always put the cover on. Always.
I've only had this much trouble once before, in years of starting seedlings in coir. Next year, I switch to Rapid Rooters.
Day 10, and the Sour Diesels are ready to pot-up to 4L pots.
By day 14, the new Grapefruit has a 1-cm radicle and is ready to plant in coir. Meanwhile, the 2 new Big Bud seeds swelled, looked like they were going to grow a radicle, then never did. By day 19, they have turned to mush. I suspect something wrong with those seeds, or they just don't like a germination mat as warm as 30°C.
So, that means this year's grow is just 2 sour diesel and 1 grapefruit. I haven't grown this few plants in years, so I decide to finally learn and try LBH's 4-way LST and SCROG techniques since I am going to grow in a tent this year. By the way, where is my new tent and light? The Covid-19 pandemic is affecting all of us, and shipping of everything is delayed.
Everyone is growing, and on day 15 it's time to pot-up the SDs to 4L pots!
Things are getting complicated in the grow room, as I am mixing up both seedling nutes for the GF and early-veg nutes for the SD. Speaking of, by day 17, the SD seedlings are now under a slightly brighter 45W blurple LED at 5-cm height, and are putting out leaves like gangbusters.
Meanwhile, its day 19, and the GF is ready to move into a 4L pot.
By day 21, the SDs are growing their 5th set of true leaves, and tomorrow I'll be ready ready to do the first snip of the 4-way LST.
So, LBH's famous 4-way LST and SCROG techniques start the training at a young age. Specifically, when the 5th set of true leaves have grown to about 1-cm or more. I forgot to take a before picture, but here's one of the SD's after pinching off that 5th set of leaves. Ouch, that hurt me to do, but supposedly it will force the growth of two main stems instead of one. Combined with the secondary branches 90-degrees away, that will give the 4-way plant that can be low-stress-trained (LST) to grow horizontally under the screen, to make a Screen Of Green (SCROG).
The tent and light are finally here and I spend the day getting them setup. Still waiting for the fan to setup the ventilation system, but plenty of time before I have to worry about keeping the RH and temp DOWN. Right now, I have to worry about keeping it warm and humid enough.
So, into the tent everyone goes! I'm worried about them being overwhelmed by All That Light (the SP250 in the tent is amazingly bright!), so I start off the light about 80-cm above the plants and slowly move it down to 60-cm over the next day or two.
Here's what they look like, happy in their new home. The small plant in the middle is Pamplemousse, the 2nd Grapefruit. She's about 8 days behind Sour and Diesel. Yes, I know the names aren't very original. Sour is the lankier of the two and Diesel the bulky one who seems a day or so ahead of Sour.
Each day brings more growth and a new addition to the tent. The oil radiant heater is necessary to keep the temperature up to 26°C, the fan keeps the air moving around, and I start adding containers of water to try to bring the humidity up. Here's a photo from Day 23:
and Day 24:
As mentioned above, I started the seedlings under low-wattage LEDs (15W for sprouts, 45W for seedlings). The day after pinching off the 5th sets of leaves for the SD, my tent and 250W light arrived, and I moved the girls into the tent. I didn't want to stress them with too much light all at once, so started the light 80-cm above the plants. They loved it, and started growing well. Over the next 24+ hours, I slowly lowered the light down to 70, 65, and 60-cm. I am fertigating twice a day to at least 50% runoff. I've got the temp consistent at 26°C and RH up to 50%. Still trying to bring that up a bit more.
What I am seeing: Growth remains strong, but I am seeing just a bit of leaf curl starting. I'm also having trouble keeping the outflow EC down with the larger SD plants, even with fertigating twice in a row, the second time at 80-100% runoff. My target EC at this point is 1200 (plus 70 for my well water), and I'm seeing outflow EC as high as 2200 the first time, and 1790 the second time. With the combination of the LST topping and moving to the higher-light tent all at once, I know I've put the girls under a bit of stress. I want to make sure I don't stress them further by making too many changes all at once.
- Is the leaf curl caused by light stress or something nutrient related to the high outflow EC?
- Should I focus first on getting a humidifier to bring the low RH up to 60-75% to reduce evapotranspiration (and probably reduce both the stress on the plants and the high outflow EC)?
- Or, should I start by flushing the plants to get the EC down and then increase fertigation frequency (which should deal with the high outflow EC and probably add enough water into the system to increase the RH)?
Well, I decided to do a bit of everything.
The first thing I realized was that Pamplemousse (the Grapefruit) is ready to be potted up to the next size, and all that new growth medium should take care of the high EC problem for her. I have the coco coir all prepped for it, so into a 4L pot she goes! (Note that I've also replaced the big window fan with a small clip fan. I think that big fan was adding to the excess evapotranspiration issues.)
Time for the evening fertigation, and presto! The EC coming out (1120) matches the EC of the nutrient solution I put in. So, that leaves Sour & Diesel, who've been running high for several days. My target EC is 1270 (mid-veg + my base water) with a max outflow of 1570, so let's try a couple of low EC fertigations. I don't want to add to their stress, so each one gets 900mL of 980 EC. Better. Sour's outflow EC is now 1730 and Diesel's is 1650. Still higher than I want, but getting there. It's also clear that they are loving all the light in this tent, and need to be potted up to their final 15L containers tomorrow. I start about 50L of rinsed coir soaking in 20L of CalMag solution to pre-buffer.
I also realize that when I setup the tent back on Day 22, my timer got messed up, and the lights have been coming on at 4am instead of 8am. Still on an 18/6 schedule, but it means that they've been doing their first 4 or 5 hours of growing each morning on the fertigation from the night before. That could also be contributing to the stress, especially with that double fan evaporating some moisture during the dark time. Let's fix that and give them 4 extra hours of light this evening and get them back on track for tomorrow.
Oh, and I want to try to get that RH up into the 60-75% range by replacing those little jars of water with a wide drain pan (visible on the right side of the photo above, where it is nicely reflecting some of the lovely LEDs of my Mars-Hydro SP250).
So, to re-cap, to deal with the high EC and possible leaf edge curling starting due to evapotranspiration stress here's what I did:
- Repotted the small GF into a 4L pot with fresh, pre-buffered coir and fertigated the hell of it.
- That lowered her top by 5-cm because she had been propped up even with the SDs before, so I lowered the light by 5-cm, to keep it at 70-cm for her and bringing it down to 65-cm for Sour and Diesel. Hope this doesn't make things worse, but all the other changes should help.
- Fertigated the SDs with lower EC nutrient solution. Will repeat this tomorrow.
- Replaced the oversize fan with a small clip fan. Still moves them (and air) around just fine, but should reduce evapotranspiration.
- Added a large flat pan of water next to the heater to add more moisture.
- Fixed the lighting schedule so the lights come on at 8am, when I do my first fertigation.
Loads of work today, but all good!
8:00. Lights on, times to fertigate. What's this? Why aren't the lights on? Oh, I didn't reset the timer right. They'll be on in 15 minutes. Fixing that first. Hmm. It feels cool in here. Ah, it's only 20° C. I guess with the lights off until 8am, the heater wasn't set high enough. Fix that. Oh, and that full pan of water I added definitely brought the RH up. To 83%, now a bit high. I'll have to keep a close eye on that today. I sure which I had the fancy AC Infinity fan I ordered with the auto RH/Temp monitor. Someday it will arrive...
Fertigate Mademoiselle Pamplemousse (the Grapefruit) with 1130 EC, pH 6.2. Outflow looks good at 1340. Golden. Now on to Sour and Diesel, who have been a bit high in their outflow EC, so fertigate with slightly lower EC than target of 1270. Try 1100 EC pH 6.0 and plenty of it. Diesel looks good with outflow of 1540, but Sour is still high at 1660. They will be potted up tonight, so consider it good enough for now.
Drain the new coir that has been buffering in Cal-Mag and set to soak in mid-veg nutes at higher pH (6.5) to fill up all that cation exchange capacity. Oops. accidentally doubled the yucca wetting agent, but that should be fine. It's just plant stuff.
How do I drain 50L of coir that has been buffering in 20L of Cal-Mag? It's not pretty but it works. An old, clean, cotton sheet from the rag bin.
16:30. RH is still at 81% but the temp is up to 26°C where it belongs. Everyone is looking happy.
Drain new coir again, mix in about 15L of perlite. Fill two 15L containers with mix, slightly compress, with a 4L container in the center to leave room for plants. Remove water from humidity tray in tent and placed containers in tray next to heater to warm up. Rotate containers at 18:30.
20:30. Lights will be on for a while, but I'm not staying up until 2 in the morning! So, it's time to pot them up to their final containers. I learned this trick from someone here, putting a spare pot of the same size as a placeholder when filling the larger pot in order to leave a hole. Makes potting up really easy!
And, after making a big bucket of veg nutes (no idea how much it holds, but maybe 20 liters?) it is time to fertigate well. Don't they look even happier? Oh, and yes, I did remember to increase the temp of the heater and raise the lights for the new height of the plants. The lights are at 60-cm now.
Phew! I've been up since 4 in the morning, and it is 10 at night now, so I think I deserve some sleep. I'll see how the temp is in the morning. If it is still low, I may have to shift them to having their light at night, with lights on at 20:00 and lights off at 14:00. One extra-long light cycle would get them there, but I just changed their schedule once, so don't want to muck with it too much. Does Cannabis get jet lag?
I mentioned that on Day 22 I had pinched off the 5th leaf sets, following LBH's 4-way LST tutorial (see the pic on that post or below). This is a first for me, and I'm taking it on faith that it works. I'm still trying to figure out exactly where the new growth is supposed to come for the two new primary stems. And what makes the secondary stems? Let's take a closer look. Diesel is a bit further along, but she is really bushy, so I need to do a little spreading to see what's up. (Get your mind out of the gutter. These are plants we're talking about. Although someone did call me a cannaphile in the chatroom today when I called his plants pretty girls.)
Here's what Diesel looked like right after pinching off the 5th leaf set:
And here's what she looks like now after 3 days of growth:
The straight red arrow is pointing to where I nipped off the 5th leaf set on day 22. The curved red arrow is pointing to one of the two new stems that are growing from this point. These will become the primary stems, and would each make a cola if I left it. But I'll be doing LST and more pinching off and then a SCROG, so I'll have a whole bunch of colas when I'm done. At least that's the idea.
So what about the secondaries that make this a "4-way LST". At first, I thought that the 4th leaf set would turn into stems or something, but that couldn't be right. See the orange arrows? Those are pointing at MORE new growth, this time from the leaf axils (the crotch between leaf and stem) of the 4th leaf set. Cool. That's got to be the new secondaries. As soon as these and the primaries get long enough, I'll gently pin them down and get them growing horizontally and ready for the screen.
Slept late this morning, and the plants were under the lights for an hour without fertigation. I'm not worried, since I did a late fertigation last night when I potted Sour and Diesel up to their final containers. So, let's see how they are doing:
Looking good! When I opened the tent, the temp was 26°C and the RH 63%. I'll take that. And isn't that a lovely pedestal that the little Miss Pamplemousse is on? It's just pieces of packing material from my Mars-Hydro SP250 light that were lying around. Waste not, want not! Reduce, re-use, recycle.
Fertigate the Grapefruit with EC 1120 pH 6.2 seedling nutes. Tomorrow she'll be a big girl and ready to move up to early veg nutes by my schedule. Outflow was a bit high at 1660, so I'll try an extra mid-day fertigation. The third set of leaves is coming along nicely after just two days. I expect to see the 4th set starting soon.
Meanwhile, Mesdames Sour and Diesel look like they are enjoying their new final containers. I switch the two, so Sour is now next to the heater and Diesel next to the fan (shown in the first picture). Not sure how much difference it makes, but as long as they are small enough and I don't have them under the screen, I figure I might as well keep moving them around so everyone gets a chance in every place. I'll move Pamplemousse next to the heater tonight. Fertigate with EC 1140 pH 5.9 mid-veg nutes. A bit below 1270, but they've been running high and just went into new pre-fertigated coir last night. I use a bit more than half on Diesel and don't feel like mixing up a new batch, so Sour gets it watered down. Outflow looks good at 1340 for Sour and 1490 for Diesel.
Now, to let them grow while I do some work. Have I said before that I really want an auto-watering system? This is my first grow doing frequent fertigation. In the past, it has been once a day at most. But, so far, the extra effort (and the extra light) is really paying off. I'm seeing growth in a day or two that used take almost a week. Now I understand how people can fit in more than one grow a year. I'm not looking forward to my electric bill though...
Mid-day fertigation of the Grapefruit. Target EC is 1170 right now. EC 1040 seedling nutes in. EC 1350 out. That works. But that finishes up the seedling nutes I had mixed. Might as well switch her to early-veg tonight. It's just one fertigation early.
Everyone is looking lovely!
And evening fertigation is uneventful. EC 1100 early-veg nutes in, 1350 out for Pamplemousse. EC 1270 mid-eveg nutes in for the SD, EC 1340 out for Sour and 1300 out for Diesel. The new primaries and secondaries are growing well. another day or two of this and they will be ready to stake down.
An easy day of growing. Fertigate all the plants morning and night and gently rearrange leaves on Sour and Diesel to make sure the new primary and secondary stems are getting plenty of light. They are growing well.
and so is Pamplemousse.
My knees and back are bothering me from all the bending down, and I need to be able to figure out an auto-drain system, and that's going to need the tent to be higher than 6" off the ground. I was going to buy a low plastic table, but it is $50 which seems a bit expensive. So, here's the solution. Strap three storage containers (totes, whatever you call them) together so they won't move around, put a thin piece of plywood on top of that, and then put the tent on top of that! I decided to put it on top of the wooden bookshelf that was already there, because I have just enough height on the ceiling to fit it. No more bending! Not a great picture because I need to clean up in the garage so I can back up more. But you get the idea.
The other big grow project today was putting the best 50 germinated Wild Blue Lupine seeds into rapid rooters, and then direct-seed the remaining 357 sprouted seeds outside for work. The ones in rapid rooters are already sticking their heads up after just a few hours. Sorry about the blurple light, but I didn't feel like getting better lighting for the photo.
Anyway, happy Beltaine to all who celebrate it, happy International Workers' Day for the rest of you, and have a great weekend!
First off a quick peek at the wild blue lupine. Don't worry, I'll get to the cannabis soon. But wouldn't that be a great name for a cannabis strain? If anyone ever makes a purp that looks more blue, they have got to name it Wild Blue Lupine. Anyway, they have almost all popped up and are starting to open their cotyledons. I'll probably have to plant them out soon, as I have to get them in the ground before their tap root hits the bottom of the ready rooter and starts to bend.
Okay, on to the plants you all care about seeing. Fertigate both the Grapefruit and the Sour Diesels. Sour Diesels are now onto the Late Veg nutrient formula. Temp is a bit low in the morning, so turn it up a bit for overnight and set the timer to turn off mid-morning when room heats up and the lights have been on. Outflow good for both. I notice that the Grapefruit has set its 5th node. Should be ready to be topped tonight.
Spend the day getting frustrated about building a drainage solution. No glue seems to stick to the saucers that I bought. After finally giving up, find an inexpensive 46x97-cm drain pan with a built-in drain fitting for PVC for less than US$25 including tax and shipping. Should be here Tuesday, and I think I have some PVC tubing and an elbow I can scrounge. I'll cut a small hole in the end of the tent, and have the tubing angle out and drain into a bucket next to the door to the outside.
But the evening fertigation goes great, with outflow unremarkable. Sure enough, it is time to top the Grapefruit. Pinch!
She is definitely catching up to Sour & Diesel. They weren't ready to top until day 22 and 23, and Pamplemousse wasn't even planted until day 14! She's only a week behind at this point. My hope is she will catch up in size by the time I am ready to start the flip. I think it is mostly that the SDs were outside the tent for the first 3 weeks and the GF just until it was a week old, but it might also be genetics.
Looking down you can see the primary and secondary branches ready to start extending and getting ready for the rest of the 4-way LST.
Tomorrow, I'll start building the screen for the SCROG. My screw eyes and string arrived today. And my ventilation fan is finally on its way here.
Morning fertigation is uneventful. Everyone is growing well. In fact, the grapefruit that started out 2 weeks behind the sour diesels has already caught up by a week; she is already just as far along on her day 16 as Sour and Diesel were on days 23 and 22! She ready to be potted up to her final container tonight, and even though it is a few days early, I am switching her to the mid-veg nutrient recipe. My hope is that she will be mostly caught up by the time I am ready to start the flip.
At noon, I notice that the RH is creeping up. It's all that nutrient solution outflow in the drain trays, so I empty them again. Can't wait for my big drain tray to arrive on Tuesday! And the exhaust fan to arrive, whenever.
I start a 15L pot of buffered coco coir soaking in mid-veg nutrient solution so I can pot up Pamplemousse this evening.
I raise the lights up to 70-cm, trying to get some more shoot extension on the primaries and secondaries so I can train them in a 4-way LST, but then folks in the chat room say to just go ahead and to the LST now; so here goes! First, the slightly easier one, Sour. She has always been a bit taller and less bushy. Here's the before and after.
That wasn't too bad! Now for the bushier Diesel.
Okay, that was tricky. But folks on the chatroom say I did well. Yay me!
Today's other project is building the screen for my Screen of Green. Here are the details, in case anyone else has this size (Mars Hydro 2'x4') tent. I'll be using US measurement units here, because that's where I am and what all the wood is in.
2 @ 46" long pieces of 1x3 or 1x4 wood
2 @ 20 1/2" long pieces of 1x3 or 1x4
8 @ 1-3/4" long #8 wood screws. I used what I had around, which were like these: https://www.amazon.com/Prime-Line-9035280-Screw-Phillips-Plated/dp/B074ZZFQ3S/
40 @ 1" long small screw eyes. I used these: https://www.amazon.com/gp/product/B07688N22X/
65 feet of string. I used this: https://www.amazon.com/gp/product/B01FGHTCMS/
4 ratchet hangers. I just ordered these: https://www.amazon.com/gp/product/B010PYWCX8/
Cut the wood to length. Pre-drill 2 holes in each end of the 46" long pieces, about 3/8" in from the end and about 3/4" from the sides. Use a drill big enough so the screws will fit in easily without the threads engaging. Fit the end pieces on one at a time, put the screws through the holes you just drilled, and screw slowly (so you don't split it) into the end-grain. This isn't really the strongest solution, but it won't be holding much weight. If it starts loosening up, I'll put some L brackets in the corners.
Mark off where the screw eyes will go. Put the first mark 3-1/2" from the end of the board, and the others 3" apart. Pre-drill all the holes with a small (5/32" in my case drill). Insert a screw eye in each hole and just give it enough of a twist to get started. Trust me, you don't want screw these all in by hand! Open the chuck on your drill enough so the top part of the screw eye will fit into.
Place the drill gently on a screw eye. Set your speed on slow, and gently screw it in. The drill will wobble a bit, but will be fine as long as you don't slide it down too far. Stop just a bit short of all the way in.
Tighten the screw eyes the last bit by hand, so you can line them up correctly. Here's my frame ready for a screen:
Setup your spool of string on a spindle so it will turn freely, feed the string into the first screw eye in one of the short end pieces, and pull it down to the far end. Pass it through the screw eye, through its neighbor, and head on back. Repeat until you have all the end screw-eyes filled. Then, run the string diagonally to the adjacent screw eye on a long side. From this point on, it will get harder to pull the string through, so you'll have to do it in to steps.
Run the string across, alternating over and under each string it crosses. I didn't tie knots or loops because I am lazy and this is the easiest way. If the strings end up coming apart, I'll use cable ties. When you are done, tighten everything up and tie off the ends.
Once my ratchet hangers get here, I'll attach a ratchet to each corner of my tent frame, loop the carabiner working ends around the corners of the screen frame and hook it back onto the hanger rope. Then I can adjust the screen as needed to get it the right height above my plants for a SCROG. I'll post a picture when it is installed in my tent.
Yesterday, I pinned down the two sour diesels that I had topped a week ago. So, let's see how they are looking this morning.
The three photos are yesterday before LST, immediately after LST, and this morning, less than 24 hours after LST.
And here's Diesel:
I am going to have to keep an eye on these to make sure they don't turn up before I get the drainage system installed and start the SCROG.
Oh, and here's Pamplemousse, the grapefruit, who I repotted last night and topped on Day 29. Also growing well, and should be ready for training soon.
Finally, we are finally getting some warm days, but the nights are still down to freezing, so I have the heater on. Managing the temperature has been difficult, trying to get the timing and thermostat settings on the heater right. So, last night I put them on one-day of 24/0, and I am switching them over to a lighting schedule with lights off from 14:00 to 20:00. That should help me keep the temps down during the hottest part of the day, and keep things warm at night.