Frequently Asked Questions:
1. What is the Compost Tube?
The compost tube is a 6-inch diameter cylinder running down the center of the Garden Tower. The tube has holes running down the entire length that allow red wiggler worms to travel between the compost tube and the soil. The worms feed on the kitchen scraps and leave rich worm castings behind. As you water the soil, this water collects vital nutrients as it passes through compost-worm castings and collects and drains at the bottom of the unit.
2. What is the Tower made of?
The Garden Tower body is made from 100% recyclable food-grade plastic. Its simple, sturdy construction ensures many years of trouble-free use. The plastic currently used to produce the composting vertical Garden Tower is food-grade high density polyethylene. We selected HDPE because it is free of BPA and other plasticizers and impurities that can become bio-available over time. In time, we plan to explore the available bio-based plastics to further reduce our footprint. The tower is engineered to provide ten years of resistance to UV radiation before the integrity of the tower's shell is significantly reduced; however, in many scenarios the first life of a Garden Tower could be much longer.
Currently, the core compost tube (which is not exposed to sunlight/UV radiation) is high quality potable water PVC. At the end of a tower's lifecycle, this non-recyclable component can be removed and reused as an in-ground worm composter for a garden. We are in the process of phasing out non-HDPE plastics from the Garden Tower.
3. What is Worm Tea and What Are Its Benefits?
"Worm tea" is simply water that has steeped in the Garden Tower's worm castings and compost. Worm tea contains many minerals, nutrients, and beneficial microbes essential for healthy soil. Along with worm castings, it acts as a soil conditioner and aids in the creation of colloidal humus. Poured onto foliage, it is also an odorless natural repellent for mites, white flies, aphids, and other pests. What are some example nutrient levels in "nutrient tea" produced by an active Garden Tower? (Laboratory Results)
4. How Do I Make Worm Tea?
When you pour water on the top of the Garden Tower, some of it will seep through the holes of the compost tube. Any excess water collects nutrients and eventually settles at the bottom, where it drips into the container beneath the drain. You don't actually make worm tea, the Garden Tower makes worm tea!
5. Why Do I Need Worms?
Worms are an essential part of the Garden Tower design. Worms break down the kitchen scraps quickly, allowing the Garden Tower to create the worm tea fertilizer. If, however, the gardener prefers to operate the Tower without worms and compost, it will still grow food effectively, provided fertilizer is added.
6. How Many Worms Should I Add to the "Compost Tube"?
About 1/2 cup of worms should be added as soon as you have a few inches of kitchen scraps in the "compost tube." See our resource list for sources of worms. You can even buy them as "vermipods" (worm eggs)!
7. How Often Should I Feed "Tea" to the Plants?
Whenever you find "tea" or fertilizer in your container, pour it back onto the soil at the top of the Garden Tower.
8. Where Do I Buy "Red Wiggler" Worms?
You can purchase "red wiggler" worms at bait shops, sporting goods stores, and online (see our resource list). Common earthworms are not recommended, as they will not flourish in the Garden Tower environment.
9. What Should I Put Into the Compost Tube?
One-half (1/2) cup of worms plus almost all of your vegetable and fruit scraps can go into the compost tube. Certain things will be difficult for the worms to eat and should be avoided. These include avocado pits, corn cobs, etc. The smaller the scraps that you use, the faster the worms will make vermicompost. DO NOT PUT ANY MEAT OR DAIRY PRODUCTS INTO THE COMPOST TUBE.
10. What Should I Do When the Compost Tube is Full?
Once or twice a year, you will want to empty the tube. To remove worm castings, untwist the wing nut at the bottom of the compost tube and remove the plug. Castings will then fall into the receptacle for easy collection. You can add the castings directly back into the Tower, or spread them in other gardens and pots you may have.
The Garden Tower grows a surprising number of vegetable and flower varieties. Here is a partial list of suggestions:
Amaranth (vegetable type), Arugula, Beans( Lima, bush, pole, shell, fava),Broccoli, Brussels Sprouts, Cabbage, Chinese cabbage, Cauliflower, Chard, Chicory, Collards, Cucumbers, Dandelion, Eggplant, Endive, Escarole, Gourds, Kale, Leeks, Lettuce, Melons, Mesclun, Mustard Greens, Dwarf Okra, Peas, Peppers, Radicchio, Sorrel, Spinach, Squash,Strawberries, Tomatoes (note: vines such as squash and melons grow nicely from the bottom holes, trailing onto the ground).
Angelica, Anise Hyssop, Basil,
Calendula, Catmint, Catnip, Chamomile, Chervil, Chives, Cilantro (Coriander), Dandelion,Dill, Echinacea (Coneflower), Feverfew, Flax, Garlic Chives, Goldenseal Hyssop, Lavender, Fennel, Lemon Balm, Marjoram, Milk Thistle, Mint, Nettle, Oregano, Parsley, Passion Flower, Pleurisy Root, Rosemary, Sage, Salad Burnet, Saltwort, Savory, Shiso, Stevia, Thyme, Valerian, Wormwood
Calendula, Carthamus, Dianthus, , Marigolds, Nasturtiums, Pansies, Salvia, Violas
Ageratum, Amaranth, Ammi, Aster, Bells of Ireland, Bupleurum, Morning Glory, Nigella, Petunia, Phlox, Polygonum, Poppy, Ptilotus, Rudbeckia, Safflower, Salpiglossis, Sanvitalia, Scabiosa, Snapdragon, Stock, Strawflower, Sweet Peas, Verbena, Yarrow, Zinnia
See "News: Gardening Ideas and Recommendations" for additional information on plant selection for Garden Towers.
12. How Big Should My Starter Plants Be Before I Transfer Them to the Garden Tower?
3 to 6 inches is suggested. Plants can also be started by seed.
13. Which Plants Go Where?
On top: peppers, carrots, beets, leeks, onions, garlic, eggplant, turnips, tomatoes, amaranth, and more.
Most other plants will grow from the side holes. Vines such as summer squash and compact melons grow nicely from the bottom holes, trailing onto the ground.
Balance large bushy or tall plants with compact plants to create a mosaic garden for best yield (three cabbages or broccoli cannot grow next to each other, but they can grow very nicely surrounded by lettuces or other compact veggies). Also pay attention to the rate at which various plants mature compared to others. For example, planting a cabbage which takes about 10 weeks to mature will allow for leafy green production (4 weeks) in adjacent openings until the broad-leafed cabbage overtakes the lettuces (light competition). By that time the lettuces will be near then end of their productive life. After the cabbage produces a yield you can start all over with the seeds you started for summer!
14. Can I Put Seeds Into the Garden Tower and Start Growing Plants?
Yes, but it's better to start seeds in flats, so that you transfer only the strongest, healthiest plants to the Garden Tower.
15. What Kind of Soil Mix Should I Use?
Like all container gardens, the Garden Tower requires potting soil as a growing media. Plain garden soil will not work because it will quickly compact in a pot or container, constraining the root system and depriving it of the necessary oxygen that roots need to survive. Peat-based soilless potting mixes that contain no soil are the most popular, but also the most expensive. For more information check under Additional Resources for links to soil sources. Although soilless potting mixes offer many advantages over soil-based potting mixes, they are not a requirement for using your Garden Tower, but they will provide better results. What is required is that you use some form of light, loose potting soil and not plain garden dirt.
To save money, you can make your own potting spoil. Many recipes can be found online. The easiest (but not necessarily the best) is to mix equal parts sand, loamy garden soil, and peat moss.
16. Where Does the Soil Go?
The soil goes inside the barrel and not inside the center compost tube.
17. Do I Ever Need to Change the Soil?
Likely not, but adding some compost as a soil amendment to the pockets and top of the Garden Tower every year is recommended. In many instances, the condition of the soil can improve with time for several reasons. However, excessive drying during the off-season should be avoided to prevent soil structure damage and keep compaction to a minimum. Lighter soils will have less compaction over time and thus lower maintenance. Plant roots and compost will contribute organic structure to the soil and worm activity will help maintain aeration and a steady rate of soil renewal. Avoiding woody-rooted perennial species (such as mints), or removing woody root masses between growing seasons is suggested soil maintenance for the Garden Tower.
18. Is It Possible to Over-water?
Not generally because of the drain at the bottom. All the water (worm tea) collected from the drain should be poured back in when you water your garden tower. However, you should not water more frequently than necessary or you can disrupt the soil and compost ecology.
19. How Do I Know When to Water?
If the plants look droopy or dry you need to water. But generally, it depends on the weather, the types of plants you are growing, and your soil mixture. We cannot tell you when to water. Like watering your house plants or garden, you'll get a feel for it. The drain at the bottom eliminates the possibility of over-watering.
20. What Happens to the Worms Over Winters?
There are many options for caring for your tower's ecosystem over the winter, depending on your climate and desired level of involvement. Red Wigglers can tolerate near freezing temperatures, and the tower's 8 inches of soil helps insulate their compost tube. You can remove the compost from the tube (where most of the worms will be) and transfer it to a well-drained hole in the ground covered with straw, mulch, or woody debris, and add some kitchen scraps.
If you live in an area with milder winters (Midwest) you can cover the tower with a transparent trash bag to help insulate the tower, or move the tower closer to a building, which holds heat.
If you want to grow over winter and have ample lighting indoors, transferring the tower indoors would be great, just don't water it for a week before you move it and it will be much lighter.
We have more information on our Extended Growing Resource Page.
21. Does the Container Ever Get Root Bound?
The fine roots simply contribute organics to the soil and microbes, macro-invertebrates, and even worms will recycle them. The large roots come out with the plants and get composted (often not in the tower but in my compost pile, but a portion of them can go back in the tower). The plants that will create some issues are those with woody root systems, almost all of which are perennial. For a first time gardener, we don't recommend perennials in the Garden Tower because some of them can create a lot of root mass which can be a challenge to deal with. However, an experienced gardener can use perennials they know they want to come back each year and plan accordingly. The only weedy perennials we've had that really become a problem are the woody mints.
It's important to note that the breakdown of roots often uses a lot of nutrients, so nutrient limitations are more likely to cause growth issues year to year than the actual root accumulation. Some nutrient tea's can be made with inexpensive organic plant food mixes to supplement the tower should the composting not sufficient in itself -- which for some plants, it simply cannot be (heavy feeders like tomatoes that pull a ton of phosphorus out of the soil).
22. What Do You Do With The Plants When They're Done Producing?
At the end of a season pull the plants out with the attached soil over a tray or 5 gallon bucket. Knock the soil loose from the roots and discard or compost the root/stems if they are not too woody (most veggies are annuals are are generally not woody). Take this opportunity to mix in some finished compost and/or organic soil nutrient amendment (plant food) with the used soil. Add the soil back to the pockets with new starts or seeds to give them a good start. Repeat each season.
After multiple plantings/seasons of use, it may (depending on the circumstances) be necessary to pull out all the soil and refresh it with minerals and nutrients, perhaps some more vermiculite to lighten in up, etc. However, we have towers that have been used for 3 full years and have not refreshed the soil to that extent in any of them. It's not maintenance-free, but if everything is working well it should be very easy to keep healthy compared to conventional gardens and even typical container systems mostly devoid of soil life.
Vertical organic gardening & composting anywhere!
Garden Tower: The ultimate patio farm by Garden Tower Project.