Gardening with raised planters is becoming increasingly popular with homeowners for a myriad of reasons. They allow homeowners to garden in apartments and homes without yard space; they allow homeowners with decreased mobility to garden; and raised planters help save on water, pesticides, and herbicides.
Using raised planters for gardening is slightly different than traditional gardening methods; these 11 great tips will help put you on the right path.
1. Use weather-resistant materials for constrction
Your garden planter is going to sit outside, exposed to the elements. Use weather-resistant materials during construction to extend its life. Many gardeners use pressure-treated lumber (which is now considered safe) or cedar planks to build raised planters. Avoid using railroad ties due to the creosote build-up.
2. Make the planter movable
If your planted will set on your deck or patio, it's important to build it so it is movable. You can easily do this by mountaing heavy duty, rolling casters on the bottom corners and in the center if the planter is long.
3. Don't built it too wide
It's important to be able to reach into the middle of the raised planter, to tend to plants. Building a planter that is too wide will make this challenging; at most build planters 4' across so you can access the entire thing.
4. Drill drainage holes
Any planter that has a solid bottom on it, and is not open to the ground beneath, needs to have drainage holes. If you've built the planter yourself make sure to drill some holes in the bottom platform to allow the excess water to drain.
5. Use chicken wire or mesh for rodent prevention
Small critters such as mice and moles can tunnel through the soil and make their way up into your raised planters. Before filling your planter with potting soil, lay chicken wire or mesh down in the bottom to keep rodents from digging their way into your planters.
6. Lay down a weed barrier
If your plants are just framed in on the sides, and sit directly on ground, a weed barrier should be put in place before adding the potting soil to the frame. A layer of carboard or newspaper will suffice in the bottom of the planter.
7. Fill with soilless plant mix
Use a commercial potting soil -- that doesn't really contain any soil, but instead a mix of peat moss, perlite, and vermiculite -- to fill your planters. Unlike gardening soil, these mixes are free of weed seeds and insects, and are formulated to be lightweight with excellent water hold capacity. If you're feeling extra ambitious, you can make your own using the directions at The Old Farmer's Almanac.
8. Avoid soil compaction
One of the benfits to using soilless potting mix in your planters, is its light, airy texture. This gives roots plenty of room to grow. Make sure to avoid walking on the potting soil to prevent compaction that will inhibit root growth.
9. Decrease plant spacing
Compared to traditional, in-ground gardening, plants can be spaced closer together in raised planters. Compost and fertilizers are more concentrated and can support higher plant numbers.
10. Consider how plants will shade each other
When planting, take into consideration mature plant sizes, putting tallest plants at the back of the planter or on the northern side to avoid shading out shorter varieties.
11. Mulch after planting
After filling your raised planters with plants, apply a couple inches of mulch to the top of the potting soil to reduce weeds. Be sure to avoid touching the stems of the plants. Good Housekeeping can help you choose what mulch to use, if you are unsure.
12. Refresh potting soil
Before using the raised planters in a following growing season, mix in 2-4" of finished compost to add organic matter and nutrients back to the potting soil. Over time the organic matter breaks down and nutrients are depleted by plant uptake.