How to Replace St. Augustine Grass With Food

St. Augustine grass is expensive, thirsty, and useless. It needs fertilizer to look decent, water twice a week to survive, and it still gets chinch bugs and takes a half day every two weeks to maintain. You could grow food in that same space.

This post walks you through exactly how to kill St. Augustine grass and replace it with food, step by step, without herbicides if you choose.

Step 1: Pick Your Replacement Strategy

Before you pull one blade of grass, decide what is going in. Your replacement plants determine how you prepare the soil and what you do with the grass.

If you are going to a food forest, sheet mulching is your best move. You can plant directly into the mulch layer with minimal soil prep. If you are putting in raised beds or a vegetable garden, you have more options including cardboard sheet mulching or solarization. Pick one method and commit. Mixing them creates more work, not less.

Step 2: Solarize or Sheet Mulch to Kill the Grass

Sheet Mulching (the easier method)

Lay overlapping sheets of plain cardboard directly over the grass. Wet the cardboard thoroughly so it conforms to the ground. Cover it with 4 to 6 inches of wood chip mulch immediately. Do not skip the wetting step. Dry cardboard does not form a seal and grass pushes right through it.

Wait four to six weeks before planting into this layer. The grass underneath breaks down and feeds the soil while the cardboard smothers the roots. Our full sheet mulching guide covers the details: sheet mulch to kill grass the easy way.

Solarization (works faster in summer)

If you want faster results, clear the area and lay clear plastic sheeting tightly over the grass. Pin the edges with rocks or stakes to seal it. In Florida summer heat, solarization kills grass and weed seeds in four to six weeks. This method works best June through August when soil temperatures under the plastic reach 140 degrees or higher.

Step 3: Plan Your Lawn-to-Garden Layout

Walk your space after the grass is dead and think in terms of sun hours and traffic patterns. Put your tallest plants on the north edge so they do not shade everything else. Leave a walking path through the planting area so you can reach everything without stepping on roots. A 3-foot-wide path every 6 to 8 feet is enough.

UF/IFAS explains how to kill turf without chemicals in Nonchemical Weed Control for Home Landscapes and Gardens.

Step 4: Plant Perennials First

Perennial plants anchor your food garden long-term. Plant them before annuals so the perennials do not get shaded out or disturbed as you fill in the rest. In a grass-to-food-forest conversion, moringa, pigeon peas, and fruit trees go in first. These are your structure plants. Everything else fills in around them.

If you want edible ground cover to finish the job, perennial peanut is the best choice for sunny areas. See how to use it in our guide on perennial peanut as a Florida ground cover.

Step 5: Fill Annual Beds Last

Annual vegetables go in after your perennials are planted and mulched. Use the in-between spaces for short-season crops like beans, sweet potatoes, and greens while your trees and shrubs are still small. Annual beds fill in the gaps for the first one to two years while the perennial structure grows up around them.

Step 6: Maintain the Edge

St. Augustine grass sends runners. It will try to reclaim your new planting area from every edge. Trench the border 4 to 6 inches deep around your planting area and check it monthly. A sharp edging tool run along the trench once a month keeps the grass from coming back without chemicals. Stick to this habit for the first full year.

Key Takeaways

• Sheet mulching with cardboard and wood chips kills St. Augustine without herbicides.
• Plant perennials first so they anchor the food garden long-term.
• Trench the edges monthly for the first year to stop grass runners from reclaiming the bed.
• A grass-to-food-forest conversion can be done in phases starting with one section at a time.

The Southern Grower's Hub has printable lawn-to-garden layout plans and a step-by-step conversion calendar built specifically for Florida zones.

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