Large deep cracks in flower bed of a 9 year old home, will not close-up with water/mulch/etc.
Our home is located just east of 35N in Round Rock. The soil is basically brown or red clay. We dug a flowerbed across the entire backyard upon moving in 2 1/2 years ago. We filled the bed with commercial garden soil and added mulch after planting, We are now noticing large deep cracks in the soil which do not closeup with water, I would appreciate any advice and recommendations you could possibly provide.
I am assuming the cracks are in the native soil adjacent to the flowerbed, not in the flower beds themselves. The likely reason the cracks have not filled is that inadequate time and water has been present to allow for full rehydration of the bulk soil. The extended drought throughout central Texas has resulted in the dehydration of many of the clay soils (both surface and subsurface). Soils such as the Houston Black clay can decrease in volume by 10-15%. This is observed in the formation of large cracks and also by the loss in soil height. Even with when the cracks are filled with water, the movement of this water into the bulk soil (between the cracks) can take days per inch. As a result, much of the water simply runs down into the subsoil where it slowly wets the soil and over months allows the cracks to disappear. There is not anything one can do to speed the process outside of apply irrigation water on a near daily routine.