Icy Grape F4

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Icy Grape F4


This journal will cover the cultivation, evaluation, and selective pollination of the F4 generation of my IGF3No.1_11 line breeding with the goal of creating an improved F5.


I’m going to germinate 45 seeds of IGF4No.11 stock using my sterile paper-towel method, and then grow the seedlings inside a sterile high dome humidity tray. Initially the seeds will go into root plugs.

From first true leaves on plants will be in 70/30 coir/perlite with fertigation solution based on Jack’s 321, Si, & H2O2. Initial EC will be 400 (combined), but I will increase by 100 microsiemens per week until I reach 1000, and at that point I’ll step up 200 microsiemens per week until I’m satisfied that I’m overdoing it. From there I’ll back off.

The mother of all these seeds was vigorous, mold resistant, early to mature, produced a very dark anthocyanin level in the flower without cold or wide dif, and carried fruit candy flavors through to cure. I tried to revegetate the mother plant, but failed.

The father was a vigorous, resinous plant, with gynodioecious traits.

Further decisions will be based on observations and comparisons to prior work. To the extent it’s possible, I will preserve clones of plants.

Grow Space:

Seedlings will be under an HLG 65 4k at 40”. For vegetative growth my 36”x36” vegetative tent will do. I have both an HLG 100 V2 4k and a 3k light in there now.

The flowering tent is lit by an HLG 600 R-Spec. I have a 27 gallon tote for a reservoir. I’ll use a self-draining tray setup and I’ve got various watering halos and drip heads. 


  • Identify a female equal to or better than their mother
  • Identify a desirable gynodioecious pollen donor
  • Produce F5 seeds (regular and gynoecious)

Let’s Goooooooooo!

Posted : 02/15/2022 8:39 am Andrey_J_, Soil Sheppard and NYWeedMan liked
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Posted : 02/15/2022 3:17 pm

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Posted : 02/15/2022 3:17 pm

I just soaked 45 seeds in undiluted 3% H2O2 for 10 minutes. Then I diluted with filtered water. I’ll let them soak overnight on a warm shelf.

Posted : 02/15/2022 3:41 pm

I went directly into rapid rooter plugs with all seeds. No signs of germination yet. They’re in a seedling tray under a tall humidity dome covered by paper towels to diffuse the light from the HLG 100s.

Posted : 02/16/2022 12:46 pm

Lots of life under the humidity dome. 5/45 sprouts are up above “soil line.” Many more visibly active inside the rooting plug.

Posted : 02/17/2022 12:51 pm

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Posted : 02/18/2022 10:27 am

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I haven’t opened the dome since I first closed it. This is survival of the fittest; If the seedlings can’t shed their shell on their own, or if they stretch and can’t recover, so be it.

Posted : 02/19/2022 11:45 am Andrey_J_ liked

I’m going to make the first round of eliminations tomorrow based on the following:

  • seeds that haven’t germinated yet
  • sprouts that haven’t shed seed shells
  • elongated stems that are flopping over
  • malformed cotyledon or true leaves

I estimate that will eliminate 20/45.

Posted : 02/20/2022 8:37 am Andrey_J_ liked

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My estimate was exact. 25 seedlings remain. I cracked the vents on the humidity dome very slightly. I also removed the paper towels that were diffusing the light.

Posted : 02/21/2022 12:13 pm Soil Sheppard liked

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Posted : 02/22/2022 12:29 pm Soil Sheppard liked

I put the plants on a 600 microsiemens seedling solution at 6.2pH and installed an automated watering system to fertigate 4 times a day (6hr interval).

Posted : 02/23/2022 12:35 pm Soil Sheppard liked

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detail of seedling fertigation hood

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I placed the paper towel back on top of the humidity dome to diffuse the light again.

Posted : 02/24/2022 1:20 pm Soil Sheppard and NYWeedMan liked

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I made another round of eliminations based on root development. I kept the 12 plants with the best roots and transplanted them into 3”x3” coir cells

Posted : 02/25/2022 2:52 pm Soil Sheppard liked

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Seedlings are doing okay, not great. That is to say they’re not growing with the vigor a polyhybrid or F1 hybrid would typically display. Or am I just really bad at this phase of cultivation? Worth assessing, because I’m having a lot of issues getting from cotyledon to vigorous vegetative growth lately. Maybe I’m overwatering, or some other environmental condition is suboptimal.

I mixed up a new batch of solution. 2.95g of Jack’s Clone, and 5ml pH down in about 3 gallons of water. Results were 800 microsiemens at 6.1 pH. I used that to top off the previous batch, and the final EC was 700.

Posted : 02/26/2022 3:37 pm fargonaz and Soil Sheppard liked
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