Think before you till
The gardening buzz has arrived. People are talking about what they plan to fill up their containers with, what new varieties of veggies they are growing and what bulbs are popping their heads up in the garden. I love this time of year when spring is just around the corner and gardeners can't wait to get their hands dirty.
At a recent vegetable garden class the extension office hosted, I encountered several people that were starting new gardens this spring. These are brand-spanking new gardens--the ground hasn't even been broken yet. I was amazed at the renewed level of interest in growing a vegetable garden. Maybe it's the economy, or maybe it's the war and we are seeing a resurgence of the Victory Gardens. Whatever the reason--it's great.
But something disturbing was revealed in my discussions with these new gardeners, and it caused a surge of panic to run through my bones. Multiple times I heard the phrase "I'm just going to till under the grass and be ready to plant this spring." I almost jumped out of my skin picturing what horticultural trauma this would cause these people.
Bermudagrass is our predominant turf in Oklahoma. It is a warm-season grass that thrives in full sun or hellish conditions. It can withstand long periods of drought, heavy foot traffic, and even severe neglect from feedings. It is wonderful for what it does in and for our landscapes.
But at the same time, for us folks that prefer to have a few flower beds or a vegetable garden, it can be our worst enemy. It turns into the plague that creeps not only above ground, but below as well. It spreads by rhizomes below ground and stolons above ground. Rhizomes are modified stems that live below the soil and send new plants up to the surface. Stolons creep across the top of the ground and send out fresh roots wherever nodes contact the soil. A node is a part of the plant that is capable of producing new growth. That is a lot of definitions, but as any good warrior knows--it is important to understand the enemy.
Now that we understand a little more about bermudagrass and the way it grows--let's revisit the idea of tilling under this monster turf to plant a vegetable garden. When a cultivator or tiller is taken over bermudagrass it chops into countless pieces of grass. Most plants would die from this abuse, but on the contrary, bermudagrass will bounce back from this like a champion. What has happened is that each of the pieces that contain a node (the part that produces new growth) will now develop into a healthy little plant.
So where one hoped to kill the grass and have a bountiful harvest, has now been turned into a regular sod farm. The grass will be more persistent and harder than ever to get rid of. Several years could be spent trying to recover from this 'fatal' mistake of tilling under the bermudagrass. Luckily, there are chemical options to help alleviate the grass amongst the vegetables. If it weren't for these products a lot more money would have to be spent on therapy to recover from the bermuda invasion.
If you are in the situation of needing to remove turf for a garden this spring, I would highly recommend a couple other options before you grab the tiller. The first is to cut the sod out. This will not get all of the roots, but by removing the top 3 or 4 inches of soil it will keep a good deal of plants from coming back. This also gives you some usable sod to place somewhere else in the landscape if you needed to. Some chemical remediation may still be needed amongst the vegetables throughout the season.
The other route to take would be to delay your spring planting for a few weeks. Now I understand that this is difficult to do when all of your friends are out planting. The method to this approach is to wait for the grass to 'green-up.' Dormant bermudagrass can't be killed. When it has turned back to that lovely shade of green, get the glyphosate out. Glyphosate is the active ingredient in products like Round-Up and several other name brand products. You can now spray the grass, wait another week or so and the grass should be good and dead. Now you can till and begin your planting.
The ideal time to prepare a vegetable garden plot is actually in the late summer to fall. The grass is still actively growing and can be killed with a chemical or covering it with a large sheet of plastic that traps in heat and 'cooks' the plants. This is called solarization. But regardless of when you start, the important matter is that you just start. For more tips with your vegetable garden contact the OSU Master Gardeners at 405-713-1125.