Planting Guide for Field Crops

Agriculture at Colorado State University Cooperative Extensioin

no. 0.103

Planting Guide for Field Crops

by R.L. Croissant and J.W. Echols ¹

Quick Facts...

Planting rates will vary with crop variety and cultural aspects.
Dryland seeding rates are approximately 50 percent of irrigated rates except for winter wheat.
Strive toward accuracy in planting to maximize yields. Over- or underplanting may reduce yields.
Factors such as machine wear, seed size, seed shape, test weight and number of seeds per pound influence seeding rates.

This fact sheet presents information on planting and harvesting many of the field Crops raised in Colorado. It is intended as a guide only. Details as planting rates will vary depending not only on crop variety but on cultural aspects (dryland vs. irrigated, for example). For simplicity, the higher seeding rates applicable to irrigated culture have been presented for those Crops produced either irrigated or dryland. Dryland rates are approximately 50 percent of irrigated rates.

Calibrating Planting Equipment

To maximize yields, strive toward accuracy in planting. Overplanting wastes seed and may reduce yields or even ruin a crop, especially if moisture is limited. Underplanting may reduce yield potential.

Much equipment has seeding charts that indicate seeding rates for many common Crops. Factors such as machine wear, size of seed, test weight, seed shape, and number of seeds per pound influence seeding rates.

It always is a good idea to check the rate. Some Crops may not be included on seeding charts. The following information will help farmers calibrate their own equipment.

Fasten a bag or container to one, two or three spouts.
Put seed in the drill.
Collect seed from the drill as follows: 600 feet for one spout, 300 feet for two spouts, and 200 feet for three spouts.
Weigh collected seed in ounces or grams.
Use Table 1 to determine the seeding rate per acre.

Table 1: Summary data of a number of field Crops in Colorado.
Crop	Seed/lb (thousands)	Weight/bu (lbs)	Seeding rate (lbs/acre)	Usual planting date	Seeding soil cover (inches)	Planting to harvest (days)
Alfalfa	220	60	3-12	spring: 4/15-5/15 fall: 8/1-8/15	.05
Barley --spring winter	13 13	48 48	60-90 30-50	3/11-4/30 8/20-9/30	1-2 1-2	100-120
Beans -- pinto kidney small white	1.2 .9 3.5	60 60 60	60-70 80-100 30	5/25-6/10 5/25-6/10 5/25-6/10	1-3 1-2 1-2	90-110 90-110 90-120
Clover (see sweetclover)
Corn -- grain forage	1.2 1.2	56 56	8-18 8-18	4/15-5/20 4/15-5/20	1-3 1-3	100-140 85-110
Cowpeas	2.0		40	5/25-6/5	1-1.5	90-120
Millet -- proso foxtail pearl	80 220 85	56 50 56	6-20 4-12 10-20 forage 4-6 grain	5/15-6/30 5/15-6/30 5/25-6/15	.5-.75 .5-.75 .50	70-90 70-90
Oats -- spring fall not recommended	14	32	50-90	3/1-4/30	1-2	100-120
Potatoes		60	1,500-2,000	4/10-6/15	4	90-120
Rye -- winter pasture	18 18		40 80	8/30-9/30	1-2
Safflower	8-13	45	15-20	4/15-5/20	.75-1.5	120-150
Sainfoin	23	55	30-35	same as alfalfa
Sorghum -- grain forage	15 15	56 56	2-8 5-8	5/15-6/10 5/15-6/10	.75-1 .75-1	90-130 90-100
Soybeans	2.8	56	60	5/15-30	1-1.5	90-120
Sudangrass	55	40	10-20	5/15-7/1	.75-1	90-110
Sunflower -- oil confectionary		28 28	3-7 3-6	5/10-6/20 5/10-6/20	1-2 1-2	90-120 90-120
Sweetclover	260	60	9-11	same as alfalfa
Triticale -- spring winter	18 18	56 56	50-80 50-80	3/15-4/10 8/30-9/30	1-2 1-2	110-120
Wheat -- spring winter	13.5 13.5	60 60	50-70 35-45	3/1-4/15 9/10-9/25	1-2 1-2	110-120

Table 2: Calibrating drills for seeding rate.
If the amount of grain collected from 600 feet of row is:		then the pounds of grain being seeded per acre is (by row width):
ounces	grams	7"	8"	9"	10"	12"	14"
4	113	31	27	24	22	18	16
5	142	39	34	30	27	23	19
6	170	47	41	36	33	27	23
7	198	54	48	42	38	32	27
8	227	62	54	48	44	36	31
9	255	70	61	54	49	41	35
10	283	78	68	60	54	45	39
11	312	86	75	67	60	50	43
12	340	93	82	73	65	54	47
13	369	101	88	79	71	59	51
14	397	109	95	85	76	63	54
15	425	117	102	91	82	68	58
16	454	124	109	97	87	73	62
17	482	132	116	103	92	77	66
18	510	140	122	109	98	82	70
19	539	148	129	115	103	86	74
20	567	156	136	121	109	91	78
21	595				114	95	82
22	624				120	100	86
23	652				125	104	89
24	680					109	93
25	709					113	97
26	737					118	101
27	764					122	105

¹Colorado State University Extension agronomists and associate professors (retired); soil and crop sciences. Reviewed by J. Johnson, Extension crop production specialist. 2/03. Go to top of this page.
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