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.
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).
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.
Water wicks up the tower via evapotranspiration, so the best place to test the soil for dryness with your finger is a pocket in the lowest row. If the soil feels dry, a heavier watering is required (5-9 gallons), if the soil feels slightly moist a maintenance watering is all that is required (2-4 gallons). 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.
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. If your Tower is draining nutrient tea (leachate) more than once or twice per week, we suggest your allow more time between watering.
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.
The soil goes inside the barrel and not inside the center compost tube.
You will need about 8 cubic feet of potting soil. Garden Tower users typical spend $28 to $56 on a potting mix purchased locally. Like all container gardens, the Garden Tower requires potting soil as a growing media (not top soil!). 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 or coir based soilless potting mixes that contain no soil are popular, but also the most expensive. For more information check under Additional Resourcesfor links to soil sources. What is required is that you use some form of light, loose potting soil and not plain garden dirt. Organic mixes will cost substantially more than typical quality mixes and are not essential for a healthy system. We recommend you ask your nursery for prices on their "professional growers mix," this type of potting soil is light and lofty and low in fertilizer content and economical. Mix in your favorite natural or organic plant food at the rate suggested on the packaging (finished compost is a great choice!) to fortify the potting mix with minerals and nutrients as you add potting soil to the Tower. 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 loamy garden soil, peat moss, vermiculite, and compost or a good quality natural plant food.
Yes, but it's better to start seeds in flats, so that you transfer only the strongest, healthiest plants to the Garden Tower.
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!