Real experts who have grown real gardens in the real world on the Front Range tell you what you need to know to have you rooting for your very own crop of successes this summer season
By Dave Perry, Staff Writer
The good news is you don’t have to know much to successfully grow outdoor pots or containers along the Front Range, filled with amazing flowers and even some vegetables.
The bad news is, if you don’t follow a few basic rules, you’re headed for certain botanical death in a barrel, a clay pot, or an old bathtub. Dead. Dead. Dead.
You’ve seen the successes here. Streets in Breckenridge brag with massive hanging planter baskets spilling with lush, stunning flowers. A neighbor’s front porch with radiant-red geraniums so big and healthy you wonder if she buries plutonium in the soil to get the effect.
And on your front porch? Death. It was all so promising. A big, expensive ceramic pot. A vast assortment of your favorite blooms. First the alyssum withered. Then the pansies. You caught the petunias trying to run away. Finally, even the indestructible snap dragons gave up the fight, and you were left with death.
Master gardeners from the CSU Cooperative Extension service have some basic tenets of container gardening that will have you blooming your way to becoming the envy of the neighborhood. Here’s how:
The biggest rule? Drainage. Few things will kill hundreds of dollars of plants faster than soggy soil baking in the sun, stewing your plants’ oxygen-starved roots. Certain death. That big, beautiful pot with the teeny-tiny hole in the bottom that keeps getting clogged? Just throw your plants in the trash and save yourself the time it will take to watch then slowly drown.
Drill more holes. Bigger ones. Lots of them. And then make sure the container is elevated slightly off the surface so the pot drains. Test it.
Next biggest rule? Good soil. If you don’t know what you’re doing and you’re planning to dig a little free dirt out of your yard and mix a little something in to make it better? Yup. Death. The metro-area’s clay soils don’t drain. In a pot? That stuff bakes in the sun and makes bricks. Buy quality potting mix that does the magic thing all plants need: drains away excess water yet holds moisture. It should have lots of perlite and similar loaming things that keep it from packing down.
In a pot about one-gallon or less, just fill it with potting mix. In a larger pot, put about an inch of smooth gravel in the bottom of the pot before filling it with soil. Not pea gravel, but gravel the size of whole almonds or pecans. This keeps soil from clogging holes in pots too big to lift. Smaller ones can be easily lifted and cleared throughout the summer. It might be tempting to save a couple of bucks and fill that big barrel mostly with your back-yard stuff and then top it off with the goodies. Don’t. If you need to take up space in a very large container, call a master gardener for options. If they prevent draining or make the container dry too fast — you know what will happen.
The next rule? Potted plants out in the sun and wind all day need watering a lot. Probably every day. In the shade, not so much. The smaller the pot, the more frequently it needs to be watered. You’re going for “damp,” here. The soil should always feel a little damp. Not soggy. Soggy kills. Damp. Watch your plants. If the soil is always damp and they still wilt every afternoon, they’re getting too much heat or sun. Clay pots on brick patios facing south are perfect places for baking bread. Pansies? Not so much. Try and find a place where tender plants in small pots get plenty of sun, but they get a break from it during the nuclear afternoons.
And now the other big rule. Pick plants that like each other and like the same kind of life. Zinnias need a lot of sun. That much sun kills garden impatiens. If you plant them together, especially in a small pot, somebody’s going to get mad, and then they’re going to die. Most nursery plants have clearly marked instructions for bedding plants: full sun, partial sun, shade. They’re not kidding. Plant together things that like the same kind of watering, sun and soil. If it’s overwhelming, go to a garden center where someone actually knows. A few dollars more for plants that come with advice is well worth not having to watch that amazing dahlia wither and die among a barrel full of Irish moss.
One master gardener says to take it even further if you’re unsure. Take a picture of your container at midday into a garden center and a nursery assistant will not only help you pick plants, but tell you how many.
The easiest choice is containers filled with the same plants, maybe different colors. Nothing wrong with a happy pot filled with nasturtiums or wax begonias. And an easy, hardy planter? Coleus or geraniums. Beautiful but trickier? Campanulas and lobelias.
But if you want the diva, the mammoth pot-a-saurus brimming with all kinds of shapes and colors and sizes, reaching high and dangling low, heed the rules. Drainage. Sun. Water. Friendly choices.
Fertilize? You bet. All the water potted plants take drain away nutrients much faster than bedded plants. Experts recommend mixing slow-release fertilizer into the soil when you plant. Make sure it’s intended for what you’re planting, flowers and vegetables have different needs. The rule of thumb, experts say, is less is best. It’s easy to overdo it, and then you get — that’s right — death.
Make sure the pot or container drains. Check the drain holes frequently to ensure that they’re not clogged with roots or mud. You can test drainage by watering a damp plant. If the water pools on top and nothing comes out the bottom, fix the problem or suffer the consequences.