Watering and Drainage in Container Gardens
Spring is here and it’s time to think about your patio container garden. There’s nothing better tasting than the fresh herbs and vegetables that you grow yourself! Here’s some ideas on how to get started if you are considering a container garden this year.
Choose the right pot
Plastic and fiberglass pots are lightweight, relatively inexpensive, and available in many sizes and shapes. Choose sturdy and somewhat flexible containers and avoid thin, stiff ones—they become brittle with cold or age.
Containers made of polyurethane foam weigh up to 90 percent less than terra cotta or concrete containers, yet they look remarkably like their much-heavier cousins. Polyurethane foam containers resist chipping and cracking and also can insulate roots against both hot and cold temperatures, making them a good choice for potting up plants that will stay outside year-round.
Wood is natural looking and protects roots from rapid temperature swings. You can build wooden planters yourself. Choose a naturally rot-resistant wood like cedar or use pine treated with a nontoxic preservative. (Don’t use creosote, which is toxic to plants.) Molded wood-fiber containers are sturdy and inexpensive.
Metals are strong, but they conduct heat, exposing roots to rapid temperature fluctuations. Metal must be lined with plastic for growing edibles.
Drainage Holes Rule
Some people say that you don’t need drainage holes – just put rocks or packing peanuts at the bottom of your container. Not the best advice. Drainage holes in 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 – at least a half 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. The larger your pot or planter, the more holes you’ll need.
Cover the Holes
Now that you have holes, you’ll want to cover them so soil won’t fall out. 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 for this.
- Plastic Window Screening – Use rolls of plastic window screening and cut pieces to fit the bottoms of pots. This is a cheap and easy way to cover drainage holes, letting water out and keeping soil in.
- Packing Peanuts – They are cheap and work, but not recommended. First, they make an incredible mess. When you pour them into your pot, they fly all over the place, get static-y and stick everywhere. Half of them usually end up stuck to you! Also, because people are realizing the environmental impact of plastic peanuts, many peanuts are now made of potato starch. Don’t put them in your containers – when wet, they melt into a slushy soup.
- 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.
The best way to ensure good drainage is to use a good-quality potting soil. Never use garden soil, because it’s too dense for potting.
Caring for Container Plants
Water container plants thoroughly. How often depends on weather, plant size, and pot size. Don’t let soil in containers dry out completely, as it is hard to rewet. Be careful not to over water and you can use mulch to help keep the soil wet if you want.
Container plants need regular feeding. Fertilize by watering with diluted fish emulsion, seaweed extract, or compost tea. Start by feeding once every 2 weeks; adjust the frequency depending on plant response.
Since containers are focal points, you will want to give them special attention to keep them looking their best. Remove tattered leaves and deadhead spent flowers. Herbs can get bitter if you don’t trim back the flowers or long stalks (cilantro, basil). Prune back plants that get leggy or stop blooming. Keep an eye out for pests like aphids and mites.
Like anything you’ll get what you put into it but it’s fairly easy to grow and maintain a container garden. Start out small and grow things that you enjoy and try a few varieties of the same vegetable. I use one container especially for peppers and we grow 5 different varieties. Grow cherry or grape tomatoes for salads and larger meatier ones that make great sandwiches. Be careful not to put too many plants in each container. You could either crowd them out or some won’t get enough sun or water.