Special thanks to Joe of Level2 Concepts for posting this seed starting procedure on the Tower Garden Facebook page. It’s working great for me. Since it’s chilly in our home over the winter, I put the containers on a plant starter heat pad. It’s made an enormous difference in the speed of germination and health of the plant.
- Pre-soak Rockwool cubes in pH adjusted water (5.5 – 6.0). Rockwool pH of around 8 caused by lime forming on the fibers during manufacture. Your seeds/seedlings/plants expect a lower pH of 5.5 – 6.0. You can get this pH adjusted water either by taking some nutrient solution out of your TG tub or filling a bucket with fresh, clean preferably filtered water (tap water is ok if that’s all you have – de-chlorinate if possible) and adjusting the pH of water to 5.5 – 6.0 using your pH test kit and the pH Acid / pH Base solutions provided with your TG (use one drop at a time, mix, wait, retest). Note: Joe likes to make up a batch of fresh, clean filtered, pH adjusted water in an old 5-gallon water cooler jug so he has it handy for use during these seeding / seedling grow stages. Put the Rockwool in the pH adjusted solution and set them aside for at least 30 minutes to soak (longer is OK).
- While your Rockwool is soaking, take the growing tray supplied with the TG and cut the clear top cover off (if you haven’t done so already) and place it on the bottom base of your TG (we’ll be using it later on in the process).
- After the Rockwool has soaked for at least 30 minutes, remove them and give each cube a firm shake to remove excess moisture. Don’t squeeze them or you will damage the cubes’ internal structure, decreasing their ability to hold air and moisture at the right ratios (Joe uses an old salad spinner for this.).
- Place Rockwool cubes into the growing tray. Mark the bottom/right corner of the grow tray (and the top cover while you’re at it) with a sticker or a piece of tape so you have a tray orientation reference point.
- Next, regardless of how many seeds the package tells you to sow, put at least 2 seeds in each Rockwool cube. Joe’s general rule of thumb is: 2 minimum and the smaller the seed, the more of each he adds to each cube (e.g. watermelon-2, celery-3, dill-4). Later on, you can always remove what you have too much of but can’t do much if you have nothing. Get a piece of paper and draw the outline of the growing tray on it.
- Mark the bottom/right of the drawing with a dot or X indicating the sticker/tape you placed on the growing tray. As you add seeds to the cubes, draw a square inside the tray drawing and write down what seed you placed in the cube.
- Now, take that bag of vermiculite you got with the TG and put it away (not needed with Joe’s process).
- Once you have sowed all your seeds, fill the tray with 1/4 inch of fresh, filtered, pH adjusted (5.5 – 6.0) water.
- Next, place the growing tray in a WARM *DARK* LOCATION *INDOORS*.
- Next, find something (other than the original growing tray top cover) to cover the growing tray so that it is completely dark – i.e. NO LIGHT. A cardboard box flipped over works just fine… the point here is to keep the seeds in complete darkness without completely sealing them up in plastic.
- Now, LEAVE THEM ALONE UNTIL THE NEXT MORNING.
- from that point on, perform the following only ONCE A DAY: Lift the cover off the grow tray and inspect EACH CUBE (a small flashlight is helpful here). Upon inspection, if you notice ANY sign of a seed germinating in a cube, REMOVE ONLY THAT CUBE from the growing tray and place it in the growing tray top cover you placed on the base of your TG. Be sure to place the cube in the top cover at the same location it was at in the grow tray. Repeat this procedure for every cube where you see the very first signs of seed life.
- Once you have removed all the cubes that have germinated, carefully drain ALL the water from the grow tray and replace it with fresh, clean filtered, pH adjusted water. Replace the water in the grow tray EVERY DAY. Re-cover the grow tray and leave it alone until the next day.
- Now, on to the top cover (a.k.a. your seedling tray)… Once you have cubes in your seedling tray, fill it with 1/4 inch of fresh, filtered, pH adjusted (5.5 – 6.0) water. COMPLETELY REPLACE the seedling tray water EVERY DAY (when you do the same for the grow tray). However, EVERY OTHER DAY, replace the seedling tray water with half fresh, clean filtered,pH adjusted water and half nutrient solution FROM YOUR TG TUB (which, by now, you should have setup and ready to receive seedlings).
Example: Monday: 1/4 inch fresh, clean filtered, pH adjusted water. — Tuesday: 1/8 inch fresh, clean filtered, pH adjusted water and 1/8 inch nutrient solution from your TG tub. Wednesday: 1/4 inch fresh, clean filtered, pH adjusted water. — Thursday: 1/8 inch fresh, clean filtered, pH adjusted water and 1/8 inch nutrient solution from your TG tub… so forth and so on.
- As you rotate your TG 1/4 turn clockwise daily (you do this, don’t you? LOL), keep the seedling tray on the DIRECT/FULL SUN SIDE OF THE TG and rotate the tray 180 degrees each day.
- Monitor the seedlings in the seedling tray for signs of the roots starting to exit the Rockwool cubes. This typically occurs about when the seedlings are around 3 inches tall. DO NOT be tempted to place the seedlings into the TG too early!
Stagger your seed sowing in multiple trays but keep them out of the TG until you see roots exiting the rockwool and/or they are about 3 inches tall. You can delay putting them into the TG by ensuring that you provide the seedlings in the trays with the proper nutrients and TLC. The longer you delay past the optimal (seeing roots/3-inches), the more TLC you need to provide and the more risk there is of encountering grow issues such as mold, fungus, algae, pests, etc. In a sense, you become a manual TG – lots of work. Be mindful that each step is in there for a reason. Therefore, altering the process in any way invalidates the expected results. Happy Growing! -JoeD
Following this procedure should produce seedlings with thick, stubby stems and larger leaves. Just like other procedures for the TG, this is a GENERAL, BROAD SPECTRUM procedure. Expect to be fine tuning it for the particular crop you are attempting to grow.
I cut the bottom off an ice-cream bucket, placed masking tape around the side to number the rock wool so I could keep track of them.
I put black duct tape around the top to use as a cover and placed it on a plant warmer.