What happens during the next two weeks sets the course for success. It doesn't guarantee success but if you start with strong healthy seedlings for the most part you will end up with a strong finish. Things can still go wrong during the grow out but overall I don't loose very many plants anymore and when I do it is because I wasn't paying attention to detail. This may well be part of the holy grail to growing and not just soilless growing. Philosophically this applies to everything in life. A good healthy start doesn't guarantee success but it starts the organism on the right path.
Draw water a couple of days ahead of when you plan to start your seeds. This allows the chlorine to gas off. Charge your container with nutrient. I use two gallons to soak my cubes so I use 4 grams part A 2 grams part B and 4 grams part C. For simple containers I do not worry about the pH nor the EC which stands for electrical conductivity. Let's save these issues for down stream.( I know it really is important but let's get people growing without too much of the science. Plenty of time in the coming journey to absorb those details.") Let your cubes completely soak for about a half hour. Take them out and set one seed per hole in each cube. For Arugula and herbs no more than three per hole. (Make that two been on an experiment all this winter of 2021 and I am getting far better yields.)
I use the rack that Grodan makes to keep the cubes out of the water in the tray. (pictured here). I take the water we charged with seedling concentration and pour into the 1020 tray to within about a quarter inch of the bottom of the cube on the Grodan rack. (OH wait all of a sudden there is local interest in the "Permanest tray" Really get onboard this train" Yes these are "Permanest Trays" and these have seen constant use for the last six years") Cover with another 1020 tray and then cover with a humidity dome. Seeds are now warm moist and dark. Note the date and time. Check in 24 hours. You are looking for the radicle, the first tip of the root. If it is showing you are on track for about a two day 8 hr timing for the cotyledons to open. Think of them as tiny solar panels. This is a typical timing for spring summer early fall. I have been tracking this for some time and by November my rates are tending towards 2 days 16 hrs and by December I pushed into the 2 days 20 hr range and sometimes they went over the 3 day mark. I do not have the capability of recording temperature and humidity within the germination chamber but that is beyond the scope we need. It would be a fascinating investigation. What is absolutely important is that the seedlings don't get stretched…Leggy. Will they grow yes but they will grow better if they get the light at just the right point. I am begging to believe you are better exposing them to light early than waiting. So if the majority have started….Let them see the light. I assure you I don't always get this right. They eventually all get the program running and pull themselves down with their roots.
seed set Arugula on top and lettuce in the foreground. These will get covered with a solid 1020 tray and then a humidity dome
What? Yes the next ten days are critical care. Hard chargers begin right here. You need adult leaves formed and you need roots. The more roots the better. Hmm..Would someone enlighten me here. Using the same seeds week to week with all the same conditions how do you get such varied results. The end goal is to have at least two adult leaves and at least one half inch of root beyond the cube. I plant 12 to 14 lettuce seeds per week. Out of those they will all get to the two leaf stage, some beyond. Some portion will have roots two inches long and side root hairs while others are just barely sticking their shoot beyond the cube. My short answer,,, not all seeds are equal.
Beyond that some trial and error exists depending on the grow conditions of your grow room. I keep our grow room set a 68 for daytime and 58 for nighttime. Now on warm sunny days we can get to 70 in the winter. Summer condition are about keeping it cooled off which means intake of outside air and exhausting inside air. Not getting to that discussion yet. I run a dehumidifier and it is set to 65% humidity. Does a pretty decent job as my humidity meter shows a fairly steady 60%.
So quickly what is the day count now. Well lets use three days to get both cotyledons out flat. If we plant on Sunday the curtain comes off on Wednesday morning. It will be another ten days in the germination tray before these are ready for transplant.
Why is this step so critical? In order to maintain a steady production schedule you need what I will call a perfect hatch. No matter what you harvest each week, you must maintain a 100% flow at this point. It is especially important within the NFT system.
Not all seeds grow at the same rate. You can see the cubes are still attached. Leaves are nearly the same size but notice how the left plant has side roots already and the right hand plant the root is just barely clear of the cube. Both of these can be transplanted. If you wait you get out of timing. If you aren't trying to stay on a precise harvest schedule you can wait a few more days but the plant on the left is wanting a full meal deal. The other will catch up
Arugula ready to drop in the reservoir
As we continue to add material come back here. There is more to do if you are using more elaborate systems. In fact another two weeks to take your plants to the exponential growth phase.
This section will be split later in this series but for now under just the "Kratky" approach your plant roots alone dictate when they are ready for the reservoir. A few more days doesn't hurt. Better roots and a bit larger first adult leaves all fine. You don't need to rush the process. When the seedlings hit the juice it is game on.
Too much ink in my view has been wasted on cutting grow time to minimize expense and maximize profit. The energy outlay at this phase is so small and with a bit of patience the rewards are paid at the end of grow. Yes you add time to the overall timeline but at the start not waiting at the end.
As I mentioned on page two this setup is based on three inch net pots. Smaller you will need to adjust the measurements and hole size in the lid of your container. You need a small base layer to prop the grodan cube up in the net pot, Hydroton clay stones work well. Perlite won't stay in the net pot. Lava rock works too.. You want about one layer of large hydroton in the bottom. Set the 1" grodan cube in the pot and support the sides with more hydration. Your reservoir water level should just be at or slightly above the hydroton balls. You are on your way.
You may notice in some photos I am using the chunks of Grodan. They add a bit of expense but it saves cleaning and sterilizing the hydroton between each grow. I'll be adding more photos as time progresses but I want to get this up and going. Work in progress, There is a huge amount of information to cover.
Lettuce ready for transplant at 14 days. Notice two adult leaves. They don't need to be any larger than these
3181 Mill Bay Rd. #1 Kodiak Alaska 99615