Plant seed per foot, not bu. per acre. There can easily be a 30% to 40% difference in seed size dependent on variety and lot; but typically it takes 120-130 lb seed/ac to hit our maximum seeding rate targets. Calibrate drill on hard ground where you can count seed. Shoot for 21-22 seed per row ft. on 7" rows (12/ft. on 4", 18/ft. on 6", 24/ft. on 8"). For broadcast seeding, shoot for 36 - 40 seed/ft2. These are high management seeding rates. Wheat compensates well for reduced seed rates and even skips in plant stands. Equivalent yields have been obtained with half seeding rates (18/ft2) and even 18-inch row skips on 15% of the field area. Don’t give up on reduced stands. Maximum seeding rates can reduce barley yellow dwarf yield loss and provides some insurance against poor emergence.
Some seed companies now list seed size (seed/lb) on the bag. The following table is useful for determining how much seed to purchase, checking whether the drill is putting out the correct rate, and for calibrating broadcast seeding. If no information is available on seed size, a good mid-range guess for the amount of seed to purchase is 120 lb per acre.
| Seed Size seed/lb |
% Germination | ||
| 90% | 80% | 70% | |
| 10,000 | 157 | 177 | 202 |
| 11,000 | 142 | 160 | 182 |
| 12,000 | 131 | 147 | 168 |
| 13,000 | 121 | 136 | 155 |
| 14,000 | 112 | 126 | 144 |
| 15,000 | 104 | 117 | 134 |
| 16,000 | 98 | 110 | 126 |
| 17,000 | 92 | 103 | 118 |
| 18,000 | 87 | 98 | 112 |
| 19,000 | 82 | 92 | 105 |
| 20,000 | 78 | 88 | 100 |
It matters. A good target is 1" to 1.5" deep. Over 2" can reduce tiller vigor, particularly if heavy rain prior to emergence washes more soil over the seed.
Planting date is always a compromise between yield potential and frost / pest risks. Early planting can raise yield potential by increasing productive tiller count, promoting a larger plant, and prolonging the grain fill period; but early planting also exposes you to greater risk from spring freezes, Hessian fly, and aphid-transmitted barley yellow dwarf virus. For example, at Blackville it is risky to plant before Nov. 15, and we should try to finish by Dec. 1. In the northern coastal plain of S.C. the optimal planting date is about two weeks earlier (Nov. 1). Plant earlier-maturing varieties last to reduce freeze risk.