Good planting dates are important because they correlate to periods with normal, good precipitation and acceptable temperature ranges for seed germination, seedling establishment and development, and early stand production.

Old World bluestem has been established from summer plantings ranging from March to August. However, most good stands result from optimum early-season plantings. Generally, stand establishment success rate declines with the onset of hot, dry weather.

There are three superb guidelines for early planting dates. Plant Old World bluestem as soon as possible up to about June 15. Plantings after about June 1 have more risk of failure.

Initiate early planting of Old World bluestem when the elm and oak trees have reached half- to full-leaf stage, which is probably the very best guide. In south central Oklahoma, this date ranges from about late March to April 15. If you still need to finish seedbeds, remember that elms will generally flower thirty to forty days before early planting time, or the half- to full-leaf stage of elm and oak.

Otherwise, initiate earliest Old World bluestem planting immediately after the last killing freeze (32°F) date in your area, usually March 17 at Dallas, Texas, and in Oklahoma, March 31 at Ardmore, April 5 at Stillwater, and April 16 at Woodward. To adjust for a different region, remember that there is about one day's difference for every 10-mile change in latitude (north-south direction). It is wise to delay extremely early plantings when the spring weather is cold. If in doubt, use the planting dates suggested. Alternatively, initiate planting two weeks after the average last spring-freeze date for your area.

All of these planting-date guides correlate to times when the surface soil temperature is regularly at or above 60°F, which is the minimum temperature required for germination.

Sometimes you may need to deviate from these planting periods and go ahead and plant; for example, if you plant Old World bluestem (1) after mechanical or chemical brush control while the soil is still freshly tilled, (2) with irrigation options, or (3) in small-grain pasture where stock will tread in the seed or after small-grain seed harvest.

There is a research basis for certain planting dates. Planting 'Caucasian' bluestem in small grains during fall was only 14 percent as good as planting it on a prepared seedbed in spring (Dudley, 1957). Stands planted during spring in small grains were only 90 percent as good as those planted on a prepared seedbed. Small grains were harvested when the seed was mature. All herbage was removed.

Research supports early planting (Dudley, 1957; Thompson and Schaller, 1960). 'Caucasian' bluestem in north Texas produced 174 percent more stand in an early spring (March 1) versus spring (April 15) planting. Fall planting (November 1) was only 44 percent as good as the best spring planting, which suggests that about twice the seed would be required in fall to get a stand comparable to that from spring planting.

At Ardmore, Oklahoma, best stands of 'Caucasian' and 'King Ranch' bluestem were achieved when planted on April 17. March 13 and June 8 plantings produced only 33 percent and 13 percent as much, respectively, as the April 17 stand (table 1).

Some grass seeds have a response called cold-induced dormancy in which a cold shock can induce dormancy for a time. The induced seeds are then reluctant to germinate well or rapidly. Old World bluestem planted too early may be influenced by this response.

Research data illustrate the importance of correlating planting dates with expected good moisture periods (Wester and Dahl, 1983; Wester et al., 1986). These data support recommendations of spring planting dates. The grasses reported were weeping lovegrass, kleingrass, and sideoats grama. Although these forages are not in the Old World bluestem group, general observation suggests that the group has the same trends.

Selected statements adapted from this research follow. Seedlings emerged soonest when there were two initial consecutive days of water. Emergence percentage was highest when 0.6 inch of water was supplied, regardless of application patterns. All grasses needed at least 0.4 inch of water to give high germination percentages. Preferably, plants should receive at least 0.6 inch of moisture within seven days for a high germination percentage. Emergence percentage was high when plants received at least 0.11 inch of water in two to three days. Seedlings that emerged early survived better than those that emerged later. One rain of 0.6 inch germinated few seeds, whereas two rains with less total moisture germinated many seeds. These results suggest that rainfall in specific patterns and amounts may be more important in determining seedling success than total rainfall per se. These data also point out the importance of planting when there is a good chance of getting useful consecutive rains. Spring and early summer plantings fit that requirement.

Figure 11. Response of switchgrass to water injected into the seed row at planting.

The proper amount of water applied in the row with grass seed from four different grasses doubled the amount of stand from a given amount of seed (Hauser, 1986, 1987; figure 11). Old World bluestem may have a similar response. This technique has two major impacts: (1) it ensures more of a stand with whatever rate of seed you use, and (2) it may allow you to use less seed than usual.

I do not recommend reduced planting rates because tillage, labor, and timeliness considerations are of equal or greater dollar value in grass establishment, and reduced rates increase the risk of not getting stands. Hypothetically, the water in the row constitutes the first rain needed to get a good stand where two consecutive rains are required, as I discussed above, and reduces the risk of inadequate consecutive rainfall. Let me again stress the importance of planting with good subsurface soil moisture and during periods of good rains. The rate of water needed in the row is 1/3 to 1/2 gallon per 100 feet of row. You can adapt standard sprayer or liquid fertilizer equipment to use this technique, which offers the opportunity to improve grass establishment.

A capable laboratory should properly sample and test all Old World bluestem seed. Use the results to plant on a pure-live-seed basis:

(germination percentage x purity percentage) ÷ 100 = pure live seed percentage

For example, (72 percent x 57 percent) ÷ 100 = 41 percent pure live seed.
Two pounds of pure live seed per acre is generally used for all Old World bluestem narrow-row (7- to 14-inch) or broadcast plantings for pasture and hay purposes. Pure live seed at 1/2 to 1 pound per acre can yield excellent stands under good conditions. Wide row plantings require only up to 1/2 pound of pure live seed. It is unwise to plant too little seed, because seed is not the only cost control input: waiting for a stand is expensive, too. Faster-developing, denser stands may be achieved with 3 to 5 pounds of pure live seed per acre.

One pound of pure live seed of 'Plains' bluestem or 'Caucasian' naked seed contains about 775,000 or 900,000 to 1,000,000 seeds, respectively. At 80 percent germination, 2 pounds of 'Plains' bluestem provides thirty-three live seeds per square foot. At an establishment efficiency of 50 percent, sixteen plants per square foot will establish under good conditions, which would be an adequate to good stand.
The major reason to plant more than 2 pounds of pure live seed per acre would be to compensate for poor seedbeds and planting procedures.

Figure 12. First year 'Plains' bluestem established from a naked caryopsis planting. This June 4 planting following rye pasture graze-out yielded over 2.5 tons per acre the first season.

Technology is available to process Old World bluestem seed to naked caryopsis (figure 6). The major advantages and disadvantages of planting a naked caryopsis, based upon observations by Ahring et al. (1964), Dewald (personal communication), producers, and Noble Foundation personnel, are summarized as follows.

Advantages comprise added convenience in planting with various equipment, including airplanes, and quicker and more complete early emergence if precipitation and other factors are good. Disadvantages are more numerous. There is more expense and labor in processing seed. There may be up to 10 percent more physical damage to processed seed. Grain moths and other insects will cause more problems in seed storage. Germination percentage will decrease when seed is stored more than one season. There is a tendency to plant too much seed. When soil is cool, early spring planting will be harder, apparently because of caryopsis problems such as fungal infections and physical rot. Seed fungicide treatment may be wise with naked caryopsis. Soil must be warm for best stand establishment. Naked caryopsis tends to require better soil moisture relationships and can be damaged more than chaffy seed by direct fertilizer contact.

Chaffy seed is somewhat protected from physical damage, insects, and disease by the bracts, or chaff, around the caryopsis. This seed sometimes emerges and establishes better than naked caryopsis at the same seeding rate. Total emergence is satisfactory with naked caryopsis but may be better with chaffy seed. Chaffy seed tends to emerge over a longer period after each effective precipitation, whereas naked caryopsis tends to emerge faster and more completely from early precipitation. Chaffy seed spreads risk. There is not much naked caryopsis left as a germination reserve after good early emergence.

With early plantings of Old World bluestem, a first crop can die because of drought, and the germination reserve of chaffy seed can emerge with later rainfall, which can be crucial to stand success under limited moisture.

The Fitzgerald Ranch planting in 1974 was established from naked caryopsis (figure 12). That planting is possibly the earliest successful producer planting of 'Plains' bluestem and is primarily responsible for the early excellent success of the grass and increased interest in all Old World bluestem.