Covering the seed can be a problem when soil moisture extends to the surface. The soil must be pressed firmly enough to seal the seedbed but not hard enough to crust the soil upon drying. A seed press wheel can help set the seed firmly in contact with moist soil. Seed firming wheels may pick up seed if soil is too wet. If this happens, remove the firming wheels until the soil dries.
Some soils become cloddy or have a tendency to crust if they are pressed firmly when wet.
A short log chain or window weight pulled behind the planter unit can aid in covering the seed with sufficient soil and help reduce crusting. Usually these problems can be avoided only by waiting for more favorable planting conditions. Starter fertilizer may be beneficial. Attachments must be mounted in such a manner so as not to collect straw. Some furrow openers place liquid fertilizer below the seed.