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Red Clover

How and why to grow, harvest, and store a perennial red clover crop in Pennsylvania.

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Updated:

December 15, 2023

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Red clover. Photo credit: Bigstockphoto.com

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Red clover (Trifolium pratense L.) is grown throughout the northeastern United States for forage and is used in rotations for soil improvement.

Unlike alfalfa, red clover will grow moderately well in slightly acidic soils (Table 1). To obtain maximum yield, maintain soil pH at 6.5 or higher.

Table 1. Characteristics of perennial forage legumes in Pennsylvania.
Legume	Seedling Vigor	Tolerance to soil limitations: Drought	Tolerance to soil limitations: Wet	Tolerance to soil limitations: Low pH^a	Heaving potential	Persistance	Tolerance to frequent: Grazing	Tolerance to frequent: Harvest	Relative maturity^b
Alfalfa	M^c	H	L	L	H	H	L	M	Early
Birds- foot trefoil	L	M	H	H	L	M	H	H	Late
Red clover	H	L	M	M	M	L	H	M	Medium-late
White clover	M	L	H	M	L	H	H	H	Early-medium

^a pH below 6.0.
^b Maturity characteristic refers to relative time of flower appearance in the spring. This will depend not only on species but also on variety.
^c L = low, M = moderate, H = high

Red clover, a short-lived perennial, can usually be harvested two or three times per year. It is characterized by rapid spring and fall growth in relatively cool temperatures. It is susceptible to crown- and root-rotting disease complexes, contributing to its short-lived nature.

Growth habit varies from erect to prostrate. Numerous stems with large trifoliate leaves arise from the crown region each year. Red clover has a thick tap root that can grow twenty-four to thirty-six inches. Lateral roots arising from the tap root are concentrated mainly in the upper five inches of the soil. Small ovoid, pinkish, nitrogen-fixing nodules can be found on the lateral roots if the plant is actively incorporating atmospheric nitrogen into protein nitrogen.

Adapted Varieties

Look for good disease resistance and persistence in a red clover variety. Varieties resistant to northern and southern anthracnose and powdery mildew are recommended for use throughout the state. Several red clover varieties marketed in Pennsylvania have been bred for better persistence. With proper management, you can expect these varieties to persist for two to three years after establishment. Refer to the current Penn State Forage Trial Report for red clover variety performance and resistance information.

Establishment

Red clover can be established as a pure stand, with or without a companion crop, seeded with forage grass, or sod-seeded into a grass sod to improve the existing stand. Each situation has special requirements that should be considered.

Seeding red clover in the spring (April to early May) or with a spring oat companion crop in a conventionally prepared seedbed is common. The best clover stands result if oats are seeded at about one-and-a-half bushels per acre. Harvesting the oats early for silage is recommended because this will greatly reduce competition with the red clover. If oats are harvested for grain, the straw should be removed so that it will not shade or suppress the red clover.

Red clover direct seeded in the spring without a companion crop will yield less total forage than when planted with a companion crop to be harvested as forage. However, a larger portion of the forage will be red clover when seeded without the companion crop. Herbicides may be necessary when direct seeding red clover without a companion crop. Direct seedings of red clover can be made by broadcasting, band seeding, or fluid seeding. Successful establishment of red clover by the fluid seeding technique (planting in a carrier of water or fertilizer solution) depends on preparing a firm and fine seedbed before seeding and cultipacking after seeding. Fluid seeding requires special equipment; therefore, a custom applicator is recommended.

Red clover can be no-till seeded and is the easiest legume to establish using this method. Early-spring seeding in winter grains or grass pastures when the soils are honeycombed from frost has also been successful.

Red clover seeding rate is ten to twelve lbs. per acre in a pure stand and six to eight lbs. per acre when seeded with a forage grass (Table 2). Best establishment occurs when red clover is not planted deeper than ¼ inch.

Table 2. Seeding rates for red clover and a single grass in mixture.
Species	Lbs./A
Red clover	6-8
with any one of these:
Orchardgrass	4-6
Perennial ryegrass	4-8
Reed canarygrass	6-8
Smooth bromegrass	6-8
Tall fescue	8-10
Timothy	4-6

To ensure adequate nodulation, red clover seed should be inoculated with Rhizobium trifolii bacteria and a sticking agent just before seeding. Preinoculated seeds should be kept in a cool, dark place to optimize the survival of nitrogen-fixing bacteria. For additional information about nitrogen-fixing bacteria or the inoculation process, see Inoculation of Forage and Grain Legumes.

Harvest Management

Red clover quality is comparable to alfalfa quality under similar harvest schedules (Table 3). However, intake by the consuming animal is generally greater for alfalfa than red clover. Red clover quality remains relatively high with maturity, while alfalfa quality does not. This means a longer period over which high-quality forage can be harvested.