Basic Seed Starting Procedure for Schools

This seed starting procedure has been adapted for the classroom from a procedure shared by Joe of It’s a little different than what’s in the Tower Garden manual, but works well in a classroom. This procedure works best growing herbs like basil, and lettuces like arugula, red salad bowl, buttercrunch, pak choi, and black seeded simpson.  For the full procedure to use with other crops, visit

Soak the rockwool in pH adjusted water

Soak the rockwool for 30 minutes in pH adjusted water. (5.5-7.0)

Use the pH test kit that comes with the Tower Garden. Put 5 ml of water in the vlal and add 5 drops of the solution.  Compare the color with the colored dots on the test paper. For a small amount of water ,like the apple juice container in the picture, use just a few ml of the pH – or pH + at a time to adjust the pH. Don’t stress out if you can’t get the pH exactly right.  Most plants will do fine if the pH is close.

After 30 minutes, drain the water from the container.


Pour some seeds into your hand

Pour some seeds into your hand


Drop 6-10 seeds into the hole.

Pour seeds on 3X5 cards for little students to plant

Pour seeds on 3X5 cards for little students to plant

Give each student a rockwool cube and pour out several seeds onto 3X5 cards.  The students can count out seeds and place them in the hole in the rockwool.

Add about 1/4″ of water to the bottom of the tray. You want the rockwool to stay damp until the next day.

Cover the container so that all the seeds are in the dark. (A file folder works well for this.) Place container on a counter or in a cabinet.

Check each morning and evening (or when school is out) for sprouts.  Replace the water each day. Most lettuce will only take two days to sprout.

When seeds have sprouted you’ll see white fuzz on the seeds.

It’s important to uncover the seeds when they sprout and place them on the Tower Garden base and turn on the lights.

Replace the water each day with 1/4 inch of water.

After about a week, seedlings should look like this and are ready to place in the Tower Garden

This basic procedure will produce fairly good lettuce for classroom use.  If you’d like to grow better plants, visit  for a more involved process.

The Plants in My Tower Garden are Wilting

Not enough (or too much) water to the plants

  1. Check that the pump timer is set to 15 minutes on, 45 minutes off. (indoor growing)
  2. Check pH (should be between 5.5 and 6.5)
  3. Check that rockwool is pushed all the way to the bottom of the netpot.
  4. Check that holes at the top aren’t clogged.
  5. Run pump while top is open and check that water is going all the way to the top.
    If not…
    Check that the Tower Garden sections are firmly seated.
    Clean the pump (See instructions to clean the pump.)
    Pull blue hose that connects the pump to the Tower Garden and run water through it. Clean if clogged.

If everything checks out with the water, then you might have insects on your plants in the Tower Garden.

Insects and Diseases on the Tower Garden


The best way is to keep insects off your plants is to practice good Tower Garden hygiene.

  1. Don’t have plants in regular soil near your Tower Garden.
  2. Between plantings,
    • Clean netpots thoroughly and soak them in a 10/1 solution of hot water and vinegar for 30 minutes.
    • Use a wet rag to clean the inside of the pots.
  3. Keep the side of the Tower Garden clean.
  4. If you start seedlings on the Tower Garden base, replace the water daily. (Follow this seed starting procedure.)
    If you do get insects,try these ideas.  If these ideas don’t work, you’re better off pulling the plants, cleaning the Tower Garden from top to bottom, and replanting.


The best way to keep diseases from your plants is to practice good Tower Garden hygiene.

If you follow the above precautions for insects, it will be rare that you have diseases on your plants – especially if you’re growing indoors.  If you do find something on the leaves that you don’t expect, here’s a great article to help.

Weekly Maintenance of the Tower Garden

The weekly maintenance for indoor growing is usually very consistent  The water level drops about the same amount each week.

A regular outdoor watering can works well as it takes about 1 watering can per week to refill the green tub.  Don’t use softened water or very hard water.


Once the water is added, measure out 50 ml of Tower Tonic A and 50 ml of Tower Tonic B for every full watering can poured into the Tower Garden. Add the Tower Tonic separately.  (Don’t mix them)



Use the pH test kit to test the pH of the water in the green tub. Put 5 ml of water from the Tower Garden into the vial. Drip 5 drops of the solution into the vial and compare the color with the test strip. The pH should be within 5.5 and 6.5.  Use about 10 ml of the pH Up or pH Down as needed to bring the pH to the correct number. (Further Instructions come with the test kit.)


Tower Garden Setup

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.

Harvesting and Cleaning

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 from the Tower Garden is ready to be donated to the local homeless shelter.

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.

I 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.

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.

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.