Adding Topsoil

Jeff Rugg
Tue, 10 Mar 2026 21:00:00 -0700
Lifestyle

Q: We are moving into a new subdivision, and we will have room for a raised vegetable garden. From what we have seen, the soil in the neighborhood is not very good. Since we are starting from scratch, what can we do to get good soil?

A: If your house and/or the subdivision is still under construction, try to get as much good topsoil as you can for the whole yard. Good soil is the foundation for plant health. It is where the water and nutrients come from, so the more there is, the healthier your plants will be, and the less watering and fertilizing you will have to do.

If you only need to do a few beds, consider using the square foot gardening method outlined in Mel Bartholomew's book "Square Foot Gardening."
Updated: Wed Mar 11, 2026

Q: We are moving into a new subdivision, and we will have room for a raised vegetable garden. From what we have seen, the soil in the neighborhood is not very good. Since we are starting from scratch, what can we do to get good soil?

A: If your house and/or the subdivision is still under construction, try to get as much good topsoil as you can for the whole yard. Good soil is the foundation for plant health. It is where the water and nutrients come from, so the more there is, the healthier your plants will be, and the less watering and fertilizing you will have to do.

If you only need to do a few beds, consider using the square foot gardening method outlined in Mel Bartholomew's book "Square Foot Gardening."

If you can't get more good soil, you can use the double-dig method. This method replaces the bad soil with good topsoil on an as-needed basis. Everywhere that you want a plant's roots to grow should be double-dug. It is easiest with annuals and vegetables that have roots that are not going to grow very far. It becomes harder for perennials, shrubs and trees.

First, decide where the raised bed is going to be. Let us pretend it will be 4 feet wide and 20 feet long. On one end, dig one shovel depth deep all the way across the 4 feet. Remove the dirt and carry it to the opposite end of the bed, 20 feet away. Dig out a second shovel depth in the same trench, all the way across the 4 feet, but leave the soil there. Use the shovel to loosen the soil at the bottom of the trench. Add organic matter of any kind to the trench. The more composted it is, the better, although fresh material will do if it is all that is available. Mix the organic matter and the soil from the second depth.

Next, dig the first shovel depth out of the next row, all 4 feet across. Add the second trench soil and some more organic matter to the first trench, mix it, and fill trench No. 1. Dig the second shovel full across trench No. 2, add the organic matter, and mix it in. Begin trench No. 3 and add the top layer with more organic matter to fill trench No. 2. Continue until you are all the way to the other end, and finish by using the soil from the first trench, mixed with organic matter to fill in the last trench.

Since each shovel depth is 8-10 inches deep, you will have a good, deep soil. You can even use this method to go three shovel depths deep. Rototilling usually only scrapes the surface a few inches deep. Double-digging is a much better method of creating good soil.

It is very helpful to dig one layer down into the existing ground under raised beds, so that they will drain properly. This provides a transition layer of soil between the good soil in the raised bed and the poor soil underneath. If there is no blending of soil, water will not drain well into the poor soil, and that will cause the bottom of the raised bed to become waterlogged. Putting sand or gravel in the bottom of a raised bed will actually make the drainage worse in the topsoil layer above it.

Any type of wood can be used for supporting walls on a raised bed. Cedar, cypress and redwood all have natural oils that slow down the decay organisms. Wood that is treated with preservatives may be harmful to some plants. Landscape timbers from garden centers are used near ornamental plants without any adverse effect. The worry is that chemicals may leach into the soil and be absorbed by vegetables. A layer of plastic behind the board can keep the moisture away from the board, and even untreated wood will last a long time. Painted boards last even longer.

Some hardware stores carry plastic or PVC boards that are used for low maintenance decking, and they can be used as raised bed boards. Other plastic or fiberglass sheets can be used if reinforced.

An easy method to build a wall with good drainage is to use stones. Flowers and vines can also be planted between the rocks for a nicer view of the garden. Large boulders go at the bottom, medium ones in the middle and small ones on top.

Many manmade concrete wall stones stack easily and have a relatively low cost. They usually have ridges for reinforcing that make them very durable.