Drainage holes prevent water from pooling in your planter boxes, they also reduce the risk of rot because of excess moisture. So, giving your planter boxes drainage holes is a good idea.
It’s important to consider the type of planter box you’re using. Some planters require more holes than others. Wire mesh planter boxes or porous wooden ones filled with perlite or the like may provide some natural drainage. Even so, it’s best to drill some holes for safety.
Why you want to avoid poor drainage
Are you careful with how much and how often you water your planter boxes? If yes, you may think your boxes don’t need drainage holes.
Drilling holes in them may seem like extra work, especially if you’ve already settled your plants in the boxes. But poor drainage gives rise to several problems that can harm or even kill your plants.
Too much water in the planter box soil leads to a lack of oxygen for the plant. Overwatered plants can’t breathe. The leaves become yellow, and the plant starts to wilt. If the water doesn’t drain, the plant may die.
Root rot is a fungal disease that develops if the root system of the plant becomes drowned in water. It can affect any type of plant, including those that like wet soil.
Other plant diseases
Overwatering a plant can also kill the microorganisms that live in the soil. These microorganisms make the soil healthy for the plant by providing it with nutrients. Even if it doesn’t cause root rot, poor drainage can upset the soil balance and affect the plant’s health.
If your planter boxes are outside, drainage holes are a must. Even if you’re careful not to overwater your plants, the next downpour may not care one bit about it.
Planter boxes in sheltered spots may be safe from the wind. But water can still get to them and saturate the soil.
Protect planter boxes
Wooden planter boxes can rot over time. If they are constantly wet, they will deteriorate sooner. Drainage holes will protect not only the plant roots but also the planters themselves.
More on this: Waterproof Liner For Planter Boxes
How to make drainage holes in a planter box
You can drill drainage holes in plastic or wooden planter boxes without any headaches. For the task, you’ll need a simple electric drill with the right bit for the material you’re working with.
It’s best to do the drilling before you add the soil and put in the plants. Mark the holes before you start. Drill enough holes for water to drain well across the planter. Start at low speed and hold the drill straight. A sharp twist bit will work just fine for wooden and plastic planters.
Tip: Water can speed up the drilling and keep the drilling surface cool. Ask someone to spray water from a garden hose on the surface as you work.
What if you’ve already put in the plant and forgot all about the drainage holes? Taking the trouble to drill them is worth the effort.
Ask a friend or two to help you to lift the planter box on bricks or on another solid base. You need to lift it high enough to be able to go under it and drill the holes.
That’s about it. Your plants will be thankful for the drainage holes you made by staying green and healthy.
Do planter boxes need extra drainage holes if they already have holes?
Ready-made plastic planter boxes may come with a few holes. For small planters, these may be enough. But as a rule, if you’re in any doubt, make some extra holes at the bottom for safety. It will improve drainage and it’s a good precaution against some of the holes becoming clogged with pebbles, perlite, or other types of rock or glass.
Does a ceramic, stone, or metal planter box need drainage?
You may not like the answer, but yes. Ceramic and metal planter boxes are hard to drill holes through. Ceramic or stone planters may crack or break in the process. Metal ones call for some serious drilling. Unless these planter boxes come with pre-drilled holes, use planters made from other materials instead.
Does a planter box need drainage holes in its sides?
Usually no. Drainage holes at the bottom of the box should be enough. If you’re worried that the bottom holes are not enough, you can drill some extra in one of the hidden sides. Choose a side not facing a wall or another surface that the water may damage.
Do double container planter boxes still need drainage holes?
Placing a plastic container with drainage holes in it into a larger, decorative planter box can provide some drainage. But excess water that builds between the two boxes may damage the decorative box over time. Plus, you’ll have to check for water constantly. Adding drainage holes save you time in the long run.
Should I still add a drainage layer if I drill holes in my planter?
A bottom layer of stones or rocks will limit how much soil washes out of the drainage holes, further improving drainage. Plus, you won’t have as much to clean.