We’ve used a number of old water troughs as planters around our yard, the best one housing our thriving olive tree. But in general, do water troughs really make good planters?
New or used metal water troughs make great planters. Simply drill some drainage holes in the bottom and line them with permeable mesh, holed plastic, or bits of broken pots. If the planter is too deep for the potting compost you need, partly fill the planter with non-biodegradable packing peanuts.
Let’s dig down (pun intended) into the subject of water trough planters in more detail, and discover how to make and line one, whether they need drainage holes, and what you can grow in one…
Can You Use a Water Trough for a Raised Garden Bed?
Water troughs make great raised garden beds. They’re a good size and shape, and you won’t have the effort of making a raised bed from planks or pallets. They also look great in your yard.
You can either repurpose an old animal water trough (and we gardeners sure like a bit of repurposing!) or you can head down to your local agricultural supplies store and pick up a new one. The latter is a good option if you’re going for a shiny, industrial-chic look for your modern patio.
How Do You Use a Galvanized Water Trough for a Raised Garden?
So you have your water trough: how do you turn it into a raised garden bed? It’s actually a pretty simple job, and should be an easy afternoon’s project. You’ll need a drill with metal drill bits and a pair of safety goggles.
Here’s how you repurpose a water trough into a planter (and the same process applies for an old one or a brand new trough).
- The trough needs drainage, so drill holes in the base (you should wear safety goggles at this point, as there’ll be galvanized metal flying about). How many holes for drainage? That depends on the size of the trough, so just aim for a drainage hole every six inches or so
- Once you start filling the trough, it’ll get pretty heavy, so move it to its desired location now. You might want to stand it on planks for extra drainage, especially if it’s going on a hard surface. Make sure it’s level before you begin adding soil etc
- For drainage, place either permeable mesh or bits of broken pot in the bottom of the trough. Some gardeners also like to line the galvanized trough with something like plastic, to prevent any zinc leaching into the soil from the galvanized coating (we’ll look at this in more depth later)
- The chances are, your new or repurposed animal water trough is deep, so that’s going to be a large and costly amount of compost and soil going in. You can fill some of the space with a layer of packing peanuts (the standard type that don’t biodegrade)
- Now add the soil and compost to your trough. You’re ready to start planting in your fabulous new raised bed
Are Galvanized Stock Tanks Safe for Gardening?
Yes, a galvanized tank is safe for planting. There’s some concern about introducing zinc from the galvanized surface into your garden. Some gardeners don’t worry about this; however, some do line their tanks before adding the soil, just to minimize any risk.
If the tank or trough wasn’t galvanized, it would eventually corrode and become unusable, so on balance, more people are pro galvanized tanks than against.
What Do You Put in the Bottom of a Trough Planter? (How Do You Line One?)
If you want to line your trough planter, the easiest way to do this is with a plastic membrane. This will form an impermeable barrier between the trough and the soil. However, its non-porous structure causes drainage problems, so you’ll have to make drainage holes in the plastic above the drainage holes in the trough.
Mesh linings are also popular. They provide a porous layer that actually helps with drainage, and plenty of gardeners now use a mesh-like Better Than Rocks to line their planters.
Of course, if you’re old school, you can still add rocks, slate, smashed pots, or non-biodegradable polystyrene as a base layer. As we mentioned earlier, an additional layer of packing peanuts can save you from having to fill the entire planter with soil and compost.
What Grows Well in a Trough?
Remember, a trough is simply an oversized container. If something grows well in a plant plot, it should do OK in a trough. The advantage over a standard planter is that extra depth, so there’s no room for plants with deeper root systems.
When you’re designing your raised trough garden, bear in mind that all the plants will have to like roughly the same treatment. So, don’t mix succulents with thirty plants, or shade lovers with sun worshippers.
Think about plant heights when you’re planning the layout, with architectural plants at the back and small but eye-catching varieties at the front. If you’re considering trailing plants, remember that metal can become very hot in the sun, and could damage delicate training flowers and foliage.
Alpines do well in troughs, as do succulents. You could have a truly dramatic-looking cacti display. Troughs are also good as herb gardens: just make sure you add gravel to the soil if you’re growing Mediterranean herbs. The green and purple of rosemary and lavender look beautiful against the silver-colored metal.
You can also grow food crops in a deep trough, such as carrots, potatoes, tomatoes, chillies, salad leaves, and some types of allium. If you don’t have space for a vegetable patch in the garden, a trough on the patio can be a great alternative bed for your veg.
Do Troughs Need Drainage Holes?
All planters need drainage holes, without exception. Without these, water would gather in the base of the pot, giving the plants “wet feet”. This can cause the roots to rot and the plant to die.
Naturally, drinking troughs are designed to be watertight! When you first bring your water trough home (or find it living wild in a corner of your yard), your first task will be to convert it into a proper planter by adding holes.
Get the drill and some robust metal drill bits, grab your goggles, and start adding those holes. A drainage hole every six inches should be sufficient. If you then decide to line your trough, you’ll have to make holes in the liner that match up with the already-drilled drainage holes.
Do Galvanized Raised Beds Get Too Hot?
A metal container will naturally get hotter than a wooden or clay planter. Will it get too hot? This depends on a number of factors, including which zone you live in and how sunny your yard is; however most gardeners seem to think the heat is manageable.
The soil at the edge of the pot will get the warmest (hence our earlier warning about trailing plants). You can help stabilize the soil temperature with a layer of liner between the planter and the soil. Many gardeners simply choose to plant things like succulents in zinc troughs, so the higher temperature isn’t an issue.
If you’re concerned about soil temperature and don’t want to plant subtropical specimens, you can always site your trough away from direct sunlight. Choose a dappled spot with a bit of shade, and you reduce the risk of overheating.
To be honest, you can get glare from a shiny metal planter on a sunny day, so a shady spot is more comfortable for you as well as your plants.
Do Galvanized Planters Rust?
A galvanized planter or trough is metal coated with a layer of zinc. This seals the metal and prevents it from rusting. If it’s rust-free you’re looking for, a galvanized planter is an excellent option.
One thing to look out for. If the protective coating becomes scratched, scraped or dented, this gives water the chance to leach in. The galvanized surface is compromised and so the planter will rust.
What can you do if you spot a scratch on your galvanized planter? Fursty, don’t panic: it can be repaired. Sand back the rust, clean and dry the area, then apply a zinc paint (as close a color match as you can get). This should make sure that your planter stays rust-free.
This short film shows you how to repair a scratch on a galvanized steel surface. It’s a straightforward job, provided you catch it early.
Summary: How Long Will Galvanized Steel Planters Last?
There are a fair few opinions as to how long a galvanized steel planter will last! On the whole, if you take care of it and treat any rust patches and scratches promptly, you should expect upwards of 20 or even 30 years’ life from the planter.
When you see old water troughs lying about in yards and in fields, you get the idea that they’re built to last! Your refurbished trough should give you years and years of planting, and will probably outlast most of the things you plant in it. Ours sure have! 🙂