Old water tanks get new life as raised-bed gardens

Kim MacMillan, freelance writer

“Recycle, reuse, grow a greener world,” these are all phrases we hear as new-age ideas, but in reality farmers have been repairing and reusing things for centuries. Farmers are really the original recyclers using composted manure to enrich the soil and baling wire and duct tape as temporary repair materials.

Any farm with livestock or horses probably has an old water tank that won’t hold water anymore lying around somewhere. Don’t throw it away! Instead, give it new life as a raised-bed garden.

While taking a break one morning two winters ago, I happened to see the idea on public television. I don’t remember the specific show, although it was probably Victory Garden or Growing a Greener World, but all I could think as I was watching was, “Why didn’t I think of that!”

We had a number of derelict water tanks here on our farm and I had started to develop an interest in gardening after watching my parents care for their garden for years, so I was motivated to try the project. Two years later my husband and I have now doubled our water tank garden line-up from last season’s three to this spring’s six old water troughs turned into vegetable production units.

The tanks have the advantage of being slightly taller than the average wood-framed raised bed, so they are easier on your back. And the soil in the tanks dries out more quickly than most in-ground gardens so you can get into them to plant earlier in the spring. Another advantage of the water tank gardens is that the soil (which is a mixture of potting soil and compost) is more loosely packed than our clay soils here in Northeastern Indiana so weeding and pulling root vegetables such as radishes and carrots is really easy.

Here’s the step-by-step to creating your own water tank raised-bed garden.

These are examples of damage to livestock tanks. Although they have been patched so they can be used as raised-bed gardens, they would no longer hold water. As raised-bed gardens the tanks need to be able to hold soil, but will also need to drain out excess water, so small holes in the bottom of the tank are not a problem. You can repair splits and breaks using a variety of repair materials such as silicone sealant, zip ties or duct or package tape and flat plastic sheets (which can be cut from old milk jugs, two-liter soda bottles or other plastic food packaging and taped over the splits).

If there is any remaining water or slime in the tank, dump out and scrub the tank with bleach to remove any possible mold, fungus or bacteria which might be detrimental to growing healthy plants. Rinse well and let dry before proceeding to the next step.

Turn over the tank onto a tarp to catch the filings as you drill small holes in the bottom for drainage. You do not want the holes to be too large to prevent too much soil from leaching out, but you do want the tank to drain well so that the soil doesn’t stay too wet and the plant roots don’t drown.  

Keep the plant containers from previous plantings and put them in the bottom of your water tank gardens before adding the soil and compost. They serve the same purpose as putting rocks in the bottom of a flower pot to allow for good drainage, but are lighter in weight than rocks to keep your tank gardens from being even heavier if they need to be moved. Only use plant containers from healthy plants to help prevent the transfer of plant diseases.

Some examples of brand-name potting soils and garden soils, as well as homemade compost that we used in our raised-bed tank gardens. Using a combination of potting and prepared garden soils and compost is lighter in weight and less compactable than our region’s clay soil making the tanks easier to move and weeding and pulling root vegetables a snap. We chose potting soil with moisture-control beads in it as part of the mixture used in the tanks to aid in retaining soil moisture or getting rid of excess moisture as needed.

Pour in the potting soil, prepared garden soil and compost over the old plant containers and mix well.

Pat down the soil to firm it up and to get rid of air bubbles which are detrimental to plant survival.

Dig holes and put in your plants. Read plant descriptions carefully when spacing your plants to make sure to allow enough room for the plants to mature.

Water in your newly inserted plants to help them establish a root system more quickly and to remove air pockets in the soil.

Add tomato cages and plant supports as needed.

Consider labeling your plants so that you can keep track of different varieties which will help you as you decide which ones to plant next year.

The newly finished water tank raised-bed garden complete with plants, plant supports, labels to identify plant varieties and with some decoration added for fun.

Until your plants are well established and covering more ground, consider adding extra garden stakes to ward off birds from taking dust baths and your pets from using your tank as a resting spot.

Our current water tank raised-bed garden includes six tanks and three large pots and holds lettuce, carrots, radishes, beets, tomatoes, peppers, kale, herbs and flowers. We fenced it to keep out deer, our hound dog and curious livestock.

Other tips: 

• When placing your water tank garden, keep in mind the amount of sun needed for garden plants to grow. Avoid overcrowding your tanks by planting too many plants too close together. Container labels will tell you how much sun and space each type of plant will need.

• If you need to pick the tanks up to move them to a new location try the front-end scoop on your tractor or a skid loader or fork truck or the bale forks on your tractor. 

• If you want to dress up your tank gardens you can paint the outside of the tanks or decorate them with stickers. Adding pretty ornamental garden stakes or whirligigs not only adds some whimsy to your garden, but the movement of the whirligigs helps to keep birds away and the placement of stakes prevents pets from sleeping in your garden.