The Tower Garden works well in a classroom for project based learning.  It’s easy to grow lettuce and herbs indoors, fits in the corner of a classroom and comes apart for storage.  There’s no soil, no weeds, and very few bugs. Not only can plant science be taught using a Tower Garden, but math and English as well.

A curriculum that matches Indiana academic standards has been released.  Find out more here.

Here are videos from the Tower Garden company to help you setup your Tower Garden for the first time.

This video covers adding water, nutrient solution, and setting the timer.

Since I mostly grow indoors, I use a 2 gallon watering can instead of a garden hose. The video will tell you to set the timer at 15 minutes on, 15 minutes off. For indoor growing, this should be 15 minutes on, 45 minutes off because the rockwool won’t dry out as much indoors as it will outdoors.

The Tower Garden comes with directions for starting seeds in daylight. Joe of Level2 Concepts introduced me to a procedure that starts seeds in the dark. I’ve adapted his procedure a bit and have it outlined here.

Most plants like a pH of somewhere between 5.5 and 6.5. Rockwool has a natural pH of around 8.0. To give your seeds the best chance of starting, you’ll need to soak the rockwool in water that’s between 5.5 and 6.0.

1. Soak rockwool for 30 minutes or more in water with a pH of between 5.5 and 6.0.
2. Cut the bottom off a 5 gallon ice-cream container or use the bottom of the growing tray that comes in your Tower Garden with the lid removed. (I’ve also used butter containers, etc.) Put masking tape around the outside of the bottom of the ice-cream container and write numbers on the masking tape to coincide with the rockwool cubes. The ice-cream container bottom works well because you can get 10 rockwool cubes around and 4 in the middle. On a piece of paper write down the numbers and the seeds you planted.
3. Shake excess water from each cube, but do not squeeze the cube. You can also use a salad spinner to shake off the excess water.
4. Place rockwool cubes into the bottom of the growing tray or other plastic container.
5. Sprinkle seeds into the hole in the middle of the rockwool. There’s no set rule for how many seeds per rockwool. For arugula, I sprinkle 15 or 20 and don’t thin them. For bibb lettuce, I’ll plant 6 or 8 and only let 1 seedling grow. Generally the smaller the seed the more seeds you should plant. You can always thin the plants with scissors later.
6. Pour about 1/4 inch of pH adjusted water in the container.
   

   10 rockwool cubes in the ice-cream bucket bottom

7. Put black duct tape around the top of the ice-cream bucket and place over the rockwool so the seeds are in the dark. (I’ve also used a box for this.) If your house is cold, you’ll get quicker results if you use a plant starter heat mat. I got mine at Menards, but here’s one on Amazon.com so you get the idea.
   
   

   The top of the ice-cream bucket covered with duct tape.

8. Every day, replace the water with fresh pH adjusted water.
9. Check your seeds every 12 hours or so to see if any have sprouted. Most lettuce and herb seeds will germinate in 36-48 hours. Uncover the seedlings and place them in another container on the base of the Tower Garden with the lights turned on. When you see white fuzz near the seeds, you want to uncover them. This is important. If you wait too long, your seedlings will become leggy. Your goal is to have short plants with large leaves.
   

   Arugula seeds that are ready to go under lights. I break a rule here and plant the arugula on top as well as inside the hole.

   

   Good start for seedlings

   I have a 12″ fixture with a 6500k T-5 bulb that I use for seedlings. This allows me to get the light right close the plants. The closer the seedlings are to the light, the better they’ll grow. I’ve also used a regular desk lamp with a 6500k bulb to get the light as close to the plants as possible.

   

   Regular desk lamp with a 6500k bulb.

10. Once a seedling is under the light, you need to drain and replace the water every day. To do this, mix up a container (I use an apple juice container) of half pH adjusted water and half water from your Tower Garden. This will give your seedlings a little nutrient solution.
    • Day 1: Replace water with half nutrient strength
    • Day 2: Replace water with only pH adjusted water
    • Day 3: Repeat Day 1
    • Day 4: Repeat Day 2
    • etc.
11. Continue with the above until you see roots starting to exit the rockwool. Once you see roots on the bottom, it’s time to put the seedlings into the Tower Garden.

I’ve used this procedure successfully for tomatoes, peppers, various lettuces and herbs. Your mileage may vary depending on the crop and your environment.

Adapted from a seed starting procedure by Joe of Level2 Concepts.

Since I’m growing indoors, the weekly maintenance is very consistent. The water level drops about the same amount each week.

I fill up a regular watering can with tap water. Don’t use softened water or very hard water. We’re on city water and have a water softener, but this tap isn’t connected to the water softener.

Then I put 5 ml of pH down into the watering can. I’ve done this enough that I can get very close to the proper pH with 5 ml per watering can full of water. I check the pH in the Tower Garden well about once a month. You’ll need to check the pH more often until you find out if it’s consistent.

I add 50 ml of Tower Tonic A and 50 ml of Tower Tonic B to the watering can. Add A and B separately. (Don’t mix them.)

Then I pour the mixture into the Tower Garden well. As the plants get more roots, you’ll notice that more water is needed. Always balance the pH of the water you put in. If I think the water level is down due to evaporation, I may leave out the Tower Tonic for one watering can full of water.

Experiment with this to determine what works best for you. Your plants will tell you once you get it right. 🙂

Once matured, lettuces and herbs can be cut and eaten until the lettuce becomes bitter and/or bolts.  It’s good to not cut more than 1/3 of the total plant at a time.  I tend to harvest the full plant and wrap it in Saran Wrap for delivery.

Using a paint can opener, I’ll pull up on the rockwool just a little to loosen it.

Then I’ll pull up on the net pot and pull everything out.  (If the lettuce is very big, it will feel like you’re going to break the net pot.  If you do, don’t worry.  The net pots will still work fine.) This leaves the roots attached so they don’t fall into the Tower Garden. I remove the roots that have grown through the net pot, but leave the rockwool attached to the plant.  Then I wrap each plant in Saran Wrap and place them in a plastic tub with a little bit of water.  If the rockwool stays wet, the lettuce will stay fresh for several days.

This lettuce is ready to be donated to the local homeless shelter.

In order to keep bugs at bay, I’ll soak the net pots in hot water and a little bit of vinegar.

Net pots soaking in hot water and vinegar.

Using a rag soaked in hot water, I’ll wash the ports.

Using a rag soaked with hot water, I clean the pots.

Remove the top of the Tower Garden and check the holes each time you harvest. It’s important to keep the holes on top of the Tower clean. This allows all the plants to receive the water they need. If you’re seeing wilting plants on one side of the Tower, this is the first place to check.

I take a 12 penny nail and push it through the holes. The nail just fits when the hole is clear.

With regular cleaning each time you harvest, you’ll be less likely to attract insects.