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Native range grass seed can often be profitably harvested from existing pastures or rangeland. These grasses are not domesticated, so have not been bred for uniformity.
Proper harvest requires paying careful attention to the grass maturity and to correctly setting the harvest equipment.
There is no set calendar date to harvest range grasses for seed. They do not ripen uniformly, so harvesting time is often a choice between maturity and shattering.
Before harvesting, examine the stand to see if there is enough seed to justify the harvest cost. This cannot be done casually, but requires that many florets be checked to see _if they contain seed.
Examine grass florets by squeezing them with the fingers. Florets that flatten out do not contain a seed. Seeds can normally be felt and extracted from the floret.
Grass seed harvested in the hard dough stage have a higher germination and more longevity than seed harvested in the milk or soft-dough stage.
Ripening usually begins at the top of the seed head, then progresses downward. These grasses often start losing their seed about 5 to 15 days after ripening.
Harvest should normally begin when the tips of the seed heads start shattering. Grass seed stands must often be checked daily because wind and other weather conditions affect the amount of shattering.
When harvesting grass mixtures, choose the grass or grasses with the best return, since the various grasses will not mature at the same time.
Grass seed can be directly combined or windrowed, then combined using a pickup attachment. Table 1 gives some suggested combine settings for certain grass species.
Direct combining requires less time and labor, but seed losses and seed moisture contents are higher. Grasses can Windrowing, curing, and pickup combining allows seed to dry in the field, but wind can scatter windrows or rain can make the grass too wet to thresh.
¶ Table 1. Suggested Combine Settings for Certain Grass Species |
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| Grass | Cylinder Speed | Air | Concave Setting | Sieve |
| Big bluestem | 900 rpm | reduce air | 1/2 in. | |
| Sand bluestem | 900 rpm | cut off all air | 1/2 in. | remove |
| Little bluestem | 900 rpm | cut off all air | 1/2 in. | remove |
| Indiangrass | 1000 rpm | cut down | 3/8 in. | remove half |
| Switchgrass | 1500 rpm | slight air | 1/4 in. | close |
| Prairie sand reed | 1200 rpm | cut off all air | 3/8 in. | remove |
| Sand lovegrass | 1500 rpm | disconnect fan | 1/8 in. | |
| Sideoats grama | 1100 rpm | cut off most | 3/8 in. | |
| Blue grama | 1500 rpm | cut off all air | 3/8 in. | remove |
Grass seed can be dried for storage by spreading the seed out evenly, about 8 inches deep, on a clean floor. A fan should be used to blow air over the top of the seed.
Seed to be used for the Conservation Reserve Program or for commercial sale requires an analysis for germination, purity, and pure live seed. Many of these seeds require a germination period of four to six weeks in order to break germination.
Gompert, T. and Chuck Francis. "Warm season grass seed harvest: opportunities and problems". crop Production News, Vol. 7, No. 21. IANR. Univ. of Nebr. May 1987.
Tidwell, E. "Tips offered on harvesting grass seed". News release dated 9/15/87. Ag Corranunications. South Dakota State Univ.