The trench should be filled back with the soil you removed to create it so that it can be treated and create the area termites will go through to contact the Termidor SC. It will last 10 years or more in the soil.
If you are doing a perimeter treatment and there is a basement below grade, then the recommended treatment would involve rodding in addition to the standard 6 in x 6 in trench. A professional company would use a long rod attached to a truck spray rig to inject more termiticide every 12 inches to a depth of at least 4 feet. Since a homeowner does not have those tools, you could use a hollow rod or pipe, or a long drill bit (18-24 inches) to help create space to force more termiticide into the ground, ideally at least what you would use for regular treatment, which averages about ½ gallon of solution every 12 inches.
Termidor SC binds with soil and can stay in the soil up to 10 years. We highly recommend to contact the manufacturer BASF 800-526-1072 since it was applied in an off-label manner.
Per the Termidor SC label: French drains eliminate water at the footing along a foundation perimeter. They are common in hollow block foundation structures to drain water seeping from the exterior perimeter or underneath the foundation. Soil must be dry before applying to sites with French drains. DO NOT rod through the slab any closer than 24 inches to the French drain to prevent Termidor SC finished dilution seepage and/or damage to the drain or the tiles. DO NOT apply Termidor SC within 5 feet of the sump pump pit and pump. To prevent drainage/seepage from the block into the drain, DO NOT drill through hollow block foundations that border the French drain.
Once French drains have been identified and located, apply a 0.06%, 0.09%, or 0.125% Termidor SC finished dilution as follows:
1. Unplug the sump pump. Inspect sump pump pit for water. If no water is present, the treatment can be made provided the sump pump remains unplugged, or
2. if water is in the sump pump pit, unplug the sump pump and remove four cups of water from the sump pump pit. Mark the water level. Wait 10 minutes and check the water level in the sump pump pit again. If the water level has risen, there is too much seepage to perform the treatment at this time. If the water level does not rise, make the treatment provided the sump pump remains unplugged.
During application, check the sump pump pit every few minutes for the presence of Termidor SC finished dilution. If detected, stop treatment immediately and remove the contents of the sump pump pit before plugging in the sump pump again. Either apply the removed sump pump pit contents to a labeled site or dispose of the removed contents as directed by this label in the Pesticide Disposal section.
Note: For structures with French drains located adjacent to the outside of the foundation, refer to the Structures with Adjacent Wells/Cisterns and/or Other Water Bodies section of this label.
Yes, we are here to provide you with the same products the pros use, but for less. We are so happy you were able to review our How To videos. Termidor SC once put into the soil will last up to ten years.