Drainage isn’t sexy, but it is one of the keys to keeping your container garden plants from drowning.
- Drainage Holes Rule - I’ve read a lot of bad advice about how to keep your container garden plants from drowning. Some people say that you don’t need drainage holes – just put rocks or packing peanuts at the bottom of your container. Not me. I find that without drainage holes my container garden plants inevitably find themselves sitting in a soggy mess. And don't mess around with small drainage holes. They just get clogged up. Optimally, you want large drainage holes - an inch in diameter is a good place to start.
- Here’s the Drill - You can put drainage holes in almost anything by using a drill with the proper bit, or a hammer and large nail. Put in as many holes as possible – it’s ok if the bottom of your container begins to look like Swiss cheese. The more holes the better.
- Cover the Holes - Now that you have holes, you'll want to cover them so your soil won’t leach out. There are several ways to do this. The tricky part is to cover the holes without completely blocking them - to keep the soil in while letting water out. There are several options here.
- Plastic Window Screening - I buy big rolls of plastic window screening and cut pieces to fit the bottoms of my pots. This is a cheap and easy way to cover your drainage holes, letting water out and keeping soil in.
- Packing Peanuts - A lot of people use packing peanuts in the bottom of their pots. They are cheap and do work, but there are some disadvantages. First of all, they make an incredible mess. When you pour them into your pot, they fly all over the place, get static-y and stick everywhere you don’t want them to. Half of them usually end up in my hair. Also, because people are realizing the environmental impact of plastic peanuts, many peanuts are now made of potato starch. Let me tell you from experience – don’t put them in your containers – when wet, they melt into a slushy soup.
If you do use peanuts, it is a good idea to put a barrier, like plastic window screening, between the soil and the peanuts. If you don’t, the soil and peanuts mix together and at the end of the season, when you go to dump out your pot, you either have to pick out the peanuts or throw all the potting soil in the garbage - an environmental sin.
- Coco fiber, Moss or Burlap - These all make great pot liners, particularly for wire or hanging baskets. They keep soil in and aid in keeping it moist. These liners can also be used to turn almost anything into a container.
- Rocks Don’t Rock - There is a pervasive myth that putting gravel in the bottom of containers helps drainage. It doesn't - it actually encourages the soil to soak up water stay wet. Don't put gravel in the bottom of your pots.
- Better than Rocks You can also buy a product called “Better Than Rocks,” which you put over the drainage holes in the bottom of your pot or window box. It’s made of recycled plastic and you can use it repeatedly. The advantage to this product is that it’s not only great for drainage it helps the air circulation in your container.
- Ups-a-Daisy Planter Inserts - These clever plastic discs come in many sizes and fit into most round planters creating a false bottom with large drainage holes. I would only use them with very large pots that you don't need to fill with soil.