When it comes to planting wildflowers, preparation is the key to success! Simply put, better soil prep = more flowers. Preparing the planting area is a task that you do not want to overlook. If you’re sowing 5 acres or 5 square feet, the more time you spend prepping the area before seeding, the better results you’ll have.
See our guide to preparing your soil below.
- Goals Of Soil Preparation
- 4 Ways To Clear The Ground Before Planting Wildflowers
- Rototilling
- Solarization and Smothering
- Hand Tools
- Natural Herbicides
- What Type Of Soil Do Most Wildflowers Like?
Goals Of Soil Preparation
Good soil preparation is the key to success! Clear weeds, grasses, and other plants (roots and all) to make room for your wildflowers to grow and thrive. There’s a set amount of water, nutrients, and sunlight available in every planting space. By leaving other plants in place before sowing your seeds, you’ll risk creating a competitive environment where your wildflowers will be stressed as they fight for resources.
Crowding and competition can cause leggy growth (extra-long, floppy stems) and weak plants, which will jeopardize the lifelong health of your planting. We don’t recommend just throwing the seed out in the field or into grass; anyone who’s tried scattering seed without removing other plants has been sorely disappointed when their wildflowers don’t come up.
The better you prep the area, the more easily two very important things will happen:
- Your seeds will germinate quicker and stronger without competing plants shading them out and ‘stealing’ available food and water.
- Without the stress of competition early on, your young wildflowers will be better suited to compete with weeds and grasses that might try to grow back.
Planning ahead is a great idea. When you have a few weeks, months, or even an entire season to plan ahead of your planting date, you may be able to prep your soil using labor-saving, cost-effective, and eco-friendly methods.
Make certain to remove all the plant debris and roots of old grass and weeds or they’ll grow back with enthusiasm!
4 Ways To Clear The Ground Before Planting Wildflowers
Depending on how large your planting will be, and how much time you have to prepare, there are a few methods for soil preparation:
- Rototilling
- Solarization or Smothering
- Hand Tools
- Herbicides
1. Rototilling
For larger areas, a rototiller can be used to break up the ground and soften the soil. You can use a handheld rototiller, a walk-behind rototiller, or a tractor with a tiller attachment. These can be affordable to rent if you don’t own one.
Did you know that every given square foot of soil has between 900-3,000 dormant weed seeds?!
Tip: The most thorough approach is to rototill or dig the planting area, two or three times, a few weeks apart.
Rototilling multiple times allows you to intentionally bring weed seeds up, have them germinate, and then kill them off in your next tilling. Your first two passes will be aimed at cleaning weeds out of the soil, while the final pass is meant to correctly prep the soil for your upcoming planting.
If you’re tilling a lawn that’s been mowed for years, chances are your weed seed count will be on the lower end. The first pass can be done at the deepest depth of 4-6″, with a shallower tilling of just 2-3″ the following times.
If your area has been an old field that has grown and seeded itself for years, expect plenty of weed seeds in the soil. In this case, it is best to shallow till 2-3” deep two or three times over the course of several weeks rather than till deeply. Allow 2-3 weeks between each soil turning, so the weed seeds have time to germinate before you till. Then, remove the weeds, plants, roots, and debris before sowing.
Avoid any temptation to dig deeper than recommended: the deeper you dig, the more dormant weed seeds you’ll turn up onto the soil’s surface, where they can sprout faster than your wildflowers.
Careful rototilling works well for three reasons:
- It opens the soil and allows a “soft” space for emerging flower plants;
- It creates a good seedbed for germination and promotes good “seed-to-soil” contact; and,
- it removes almost all the existing grasses and weeds which would otherwise compete with your seedlings.
Solarization and Smothering
Both of these methods are aimed at killing weeds by laying materials over your planting site. It’s easy for large or small spaces, and is a very environmentally sensitive option. Solarization, as its name implies, takes advantage of the sun’s rays over time, and it takes about 4-8 weeks. Smothering requires a thick layer of material that will block out the sun to eliminate plant growth.
Solarizing Weeds & Grass
Lay clear plastic, like a painting drop cloth, over your soil. Leave the area covered for 4-8 weeks. The sun will shine down on the plastic, trapping an excessive amount of heat and moisture underneath, which will kill any existing plant life.
An added benefit of solarizing is that some weed seeds may be encouraged to germinate in the sunlight before the heat kills them off.
Smothering Weeds & Grass
Smothering can be done with heavy tarp(s), blanket(s), cardboard, or several inches of leaves or mulch, laid over the planting site. Leave the area covered for 4-8 weeks. This cuts plant life off from available sunlight and also introduces a whole lot of warmth. Weed seeds that germinate in darkness will sprout under the heavy fabric, but will then die off from lack of sunlight.
An added benefit of smothering is that it creates the perfect environment for earthworms and other soil life to eat the decaying plant growth and loosen up the soil.
Hand Tools
For a small area, the project is the same as preparing for a new garden bed. A shovel or spade and rake are usually all that’s needed. Simply dig out everything that’s growing, turn the soil, and rake the area flat and free from rocks and roots. A few rocks and some uneven spots won’t bother a wildflower planting.
Grass roots are especially important to remove so they don’t grow back along with your new wildflowers. If necessary, use a pickaxe, or the smaller handheld version called a mattock, or even a sharp spade. Then, you’re ready to plant!
Natural Herbicides
Those who are really struggling to remove tough weeds may choose to turn to chemical applications. Organic (non-synthetic) herbicides, such as acetic acid, vinegar, and other mixes, are available at most hardware stores and garden centers.
To prevent damaging the plants you’ve chosen for your landscape, always apply herbicides carefully on wind-free days.
If you’d like to remove grasses from your planting, and you’d like to use a natural herbicide spray, be sure to choose one that is intended to control ‘monocots’, or single-blade plants. Herbicides intended to kill ‘dicots’ (also called broadleaf plants) will likely kill off part of your intended planting.
When working with any weed killer: be aware that they are non-selective, which means that they will harm any broadleaf plant or tree that they make contact with, including wildflowers. It’s also important to give the herbicides time to be cleared from the soil before planting.
Note: We do not recommend synthetic herbicides, such as Roundup or glyphosate, as they can be harmful to people, pets, wildlife, and plants. For example, glyphosate can be present in the soil for up to 60 days or more after use, depending upon environmental conditions.
Which Method Is Right For You?
There are two factors that will help you to decide which one is the best for you: size and lead time: Size and Lead Time.
Size: Large or Small?
- Large spaces are more easily prepared with equipment like rototillers or tractors
- Hand tools will be just fine for prepping small gardens and containers
Lead Time: Planting Sooner or Later?
- Planting Immediately to a couple of months away: For quicker planting projects, we recommend rototilling or using hand tools to remove plant growth and existing roots. Some people rent or borrow equipment if they don’t own it, while others are happy to prep their soil by hand to keep their planting budget-friendly.
- Planting in 4-8 weeks or later: You have the option of solarization or smothering to kill off weeds and grass, and you could also make use of natural herbicides and weed killers. This approach reduces physical labor, and also allows time for the chemicals to dissipate before they can do any harm to your wildflower planting. This time frame also gives you time to work the soil with a tiller or hand tools multiple times, and for weed seeds to be repeatedly brought to the top of the soil and killed off, diminishing their overall appearance in your meadow.
What Type Of Soil Do Most Wildflowers Like?
Your soil is probably already perfect for wildflowers! Unless your soil is actually sterile, which is rare, it’s recommended that you use your soil just as you find it. The test is simple: If anything is growing in the area — even if it’s just grasses or weeds — the area should support wildflowers without concern. If you can grow weeds, you can grow wildflowers!
There are some exceptions. For instance, if the planting area had suffered a chemical spill or contamination, if you’re planting on a new construction site where the topsoil was removed, or if the soil is heavily compacted due to drought, heavy traffic, overuse, or neglect. Again, a simple way to assess the soil is by identifying what’s currently growing in it: where nothing grows, you may need to amend your soil, or find a new site for the meadow. Wildflowers are quite adaptable but will not grow on a sterile site. If your soil is heavily compacted clay, or very sandy, adding some organic matter can help improve soil texture.
Wildflowers, as we see on every roadside, are extremely adaptable and do well in poor soils.
Compost or other organic fertilizers are not necessary for growing wildflowers, and in fact, they may make the soil overly rich, inviting weeds and stifling the growth of some wildflowers.
The only absolute requirement is good drainage. Choose a place where water does not stand for longer than one hour after a rainfall.
