Most broadleaf pesticides are not residual unless over applied. It depends on the type and brand of pesticide you have applied.

The short answer is yes, sugar does help plants grow. However, excessive amounts of sucrose can be harmful to a plant. For plants growing hydroponically or in a selective medium such as in a petri dish, sucrose is often used as a carbon source for sprouting plants. Plants make sugars through photosynthesis by combining water and carbon dioxide. Plants use carbon dioxide as their main carbon source so they do not need sugar in their substrate to grow. But young plants and tissue plant clones that aren't yet efficiently producing sugars through photosynthesis can benefit from the extra carbon stored in sucrose.

Sugar water used in a plant's natural environment can also attract other organisms and bacteria. Although some may be symbiotic (help the plant), many can interfere with the plant's growth or even cause it to die.

Plants can grow in just about any medium, as long as they have water and nutrients. The problem with growing in sand, however, is the lack of water and nutrients.

Sand does not hold water the way other soils will. Sand contains practically no organic material, so there is not much in it for plants to use for nourishment. Nor does it grow the fungus species that make nutrients available to roots.

As you can see at a beach or in a sand desert, some plant species have evolved to handle these conditions, usually by sending roots down far enough to find water, or by growing very fast whenever there is a rain, or by absorbing the rainwater quickly and storing it for future use. They can only survive if there are enough nutrients mixed into the sand. Pure sand will not do.

That depends upon how deep the soil bed is and how much moisture is in the topsoil.

But here are some ballpark numbers for you:

A yard of soil will cover a 10' by 10' area to a depth of three inches. In other words, figure a third of a yard per 100 square feet for every inch of depth.

Length x width x # of inches deep divided by 324 = the number of cubic yards needed for that task.

Basal in terms of fertilizer can only refer to the amount of nutrients needed in the soil to sustain normal plant health, it is not an agronomy term per se but that is what it would mean when applied. Top dressing is the application of a product in an even manner to the surface of the soil or turf, in golf that means applying sand to make the surface smoother, to fill in holes from aeration, and to promote upward growth in golf greens.