QUESTION #21 

What is the best planting rate for alfalfa in Oklahoma? 

EXPLANATION: Ten lb/A of good alfalfa seed is equivalent to approximately 42 seeds/ft², and proper planting of 10 lb/A of pure seed in a well-prepared seedbed will result in stands of 25 to 30 plants/ft². Alfalfa stands thin naturally to about 15 to 20 plants/ft² during the first year and eventually stabilize at 5 to 8 plants/ft² in productive stands. As the number of plants decline, the number of stems per plant increases. Approximately 30 stems per ft² represents a "full stand" regardless if 30 stems come from 30 plants or from 6 plants. 

Sometimes a major concern, when evaluating a new stand, is the uniformity across the field, not the average number of seedlings per square foot. Consequently, in addition to counting seedlings on a square foot basis, one should assess how much of the field has less than 4 seedlings/ft² Several thin quarter-acre areas in each 5 acres of a large field indicates that the field will have areas that will become weedy quickly, and these weedy areas will contaminate much of the hay. 

Sowing rates higher than 10 lb/A are not required but can serve as insurance against poor seedbed preparation, poor planting equipment, and poor weather conditions following planting. 

The extra cost of $20/A for additional seed is frequently considered a good investment when seed beds are less than ideal or low-quality seed is used. In cases of fluffy or cloddy seed beds, many seedlings die before becoming established. More seed per acre may alleviate marginal establishment under some circumstances. 

Seed cost is often considered to be the major cost to the producer; however, a typical itemization of establishment cost shows that seed cost is only 15 to 20% of the total investment.

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QUESTION #22 

How deep should alfalfa seeds be planted to get a good stand? 

EXPLANATION: Seed placement depth is critical to germination, seedling emergence, and root development. Ideally, seeds should remain between 1/4" and 1/2" below the soil surface. 

Seed placed on the surface of a good seedbed (freshly developed, firm, and mellow) and then pressed with a roller or press wheel is the most common and acceptable way to sow alfalfa. 

Alfalfa seeds are small and do not contain enough energy to emerge from more than about 3/4" in loose soil. In hard-packed soil they can emerge from less than 1/2." 

Seeds that germinate on the soil surface have roots in the sunlight. They do not have soil to push against; consequently, seed coats remain on cotyledons longer. Weak seedlings result from burying seeds too deeply or leaving them on the surface.

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QUESTION #23 

When is the best date to plant alfalfa in Oklahoma? 

EXPLANATION: In some areas of the country, there is only one time for sowing alfalfa. In Oklahoma, alfalfa can be sown in late summer (fall) or in spring. During both seasons, producers should plan to plant during a relatively narrow window for best results. 

Fall Planting: Alfalfa is traditionally planted in late August and early September in Oklahoma. Fall plantings can be extended into early October if a stand can be irrigated immediately after sowing to obtain emergence. Plants coming up much after October 1 may not have adequate root development to survive the winter. A good rule-of-thumb is that alfalfa plants need five leaves before the first hard freeze (20F or colder) to survive and produce high yields. 

A properly prepared seedbed is critical to early establishment. Incorporated preplant herbicides are an option, but use should be limited to areas with severe weed problems since incorporation can be detrimental to a good seedbed (loss of moisture and formation of clods). A better alternative may be to control seedling weeds after they have emerged by applying post-emergence herbicides in early fall. 

Spring Planting: Spring-sown alfalfa in Oklahoma is more risky than fall plantings. This is primarily due to more problems with strong drying winds, insects, weeds, and intense rains. The combination of intense rains and wind tends to crust soil and inhibit emergence. When establishing alfalfa in the spring, planting between mid-March and mid-April is critical. This allows seedlings enough time to develop good root systems prior to the onset of high temperatures (above 90F). 

Multiple pest-resistant varieties, excellent seedbeds, and preplant incorporated herbicides is even more important with spring plantings. Spring sowing is more likely to be successful in the eastern half of the state where rainfall is higher. It can be successful statewide if irrigation is used. 

Spring-sown alfalfa stands normally have only one or two cuttings during the first summer. Even in subsequent years, yields for spring-sown stands tend to be lower than those established in late summer. It is frequently advisable to consider planting an annual short-season forage crop in spring and then harvest it in time to plant alfalfa in late summer.

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QUESTION #24 

Should alfalfa be dusted in? 

EXPLANATION: If dusting in refers to planting on a poor (powdery or cloddy) seedbed, then dusting in is not advisable. 

Alfalfa seed is normally planted 1/4" to 1/2" deep into dry soil, and a rainfall event of 1/2" to 1" is needed for germination and establishment. This type of planting is often referred to as dusting in. Even when alfalfa seed is placed in moist soil at 1/4" to 1/2", the soil often dries before the seeds germinate. 

Sowing alfalfa by dusting in during the last week of August or the first week of September usually assures adequate time and probabilities for several adequate rainfall events before the onset of cold weather. If sowing is delayed until late September or early October, dusting in is not advisable. Late planting should be done with a shoe or disk opener that pushes back dry soil, allowing seed to fall onto moist soil and be pressed in with press wheels or rollers. 

When it is impossible to prepare a firm seedbed because of excessively dry soil conditions, seeds should be dropped on the soil surface and pressed in 1/2" to 3/4" beneath the surface. Rains will pack the soil around the seed, leaving them 1/4" to 1/2" deep.

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