Growing your own alfalfa is an easy and fun project. Alfalfa hay is ideal for livestock, and you can provide rotational grazing in the fields throughout the year. Most of us know about alfalfa sprouts, which are yummy and nutritious, but we rarely think about growing alfalfa as a cover crop or to provide nutrients to the dirt, or as fodder for cattle, horses, and sheep.
The purple blooms on this plant are well-loved by pollinators and alfalfa tea is popular with many folks because of its high vitamin content. You don’t need a huge amount of space to grow alfalfa, though it depends upon what you are growing it for, because you need a large field if you plan to feed your farm animals.
This guide offers guidance on planting alfalfa, how to provide the best growing conditions, and treatment of common pests and diseases. By the end of the article, you will feel confident and excited about planting and harvesting your own alfalfa.
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Quick Care Guide
|Scientific Name||Medicago sativa|
|Height & Spread||2-3 ft tall, 2-3 ft spread|
|Soil||Sandy loam, silt loam, clay loam|
|Water||1 inch per week|
|Pests & Diseases||Weevils, aphids, blister beetles, leaf spots, root and crown rot|
All About Alfalfa
Medicago sativa is also known as lucerne but commonly goes by the name of alfalfa. It is a perennial legume that is native to southwest Asia but is now cultivated worldwide for fodder, to improve the soil, and as a food source for pollinators. It is well suited as a cover crop and as an additive to compost since it is nutrient-rich.
Also, the option to seed your field with annual grasses has been shown to help with weed and erosion control while also providing a more digestible fiber for your animals during rotational grazing.
All parts are edible, though the leaves can become bitter tasting to humans as the plant matures. The purple blooms are a pleasant addition to salads, and alfalfa sprouts are commonly grown for human consumption.
The reason alfalfa is high in vitamins and minerals is that its taproot can grow up to 20 feet deep, allowing it to grab nutrients that other plants can’t reach. The plant grows erect up to 2 to 3 feet tall with a 2-3 foot width. The leaves have three leaflets (trifoliate leaves) with an oval/oblong shape and serrated tips. The leaves are smooth on top and slightly hairy underneath. The flower blooms produced on racemes are typically light purple, though you may see white and yellow. Most seeds are held in spirally coiled smooth pods, each containing 2-8 seeds.
Alfalfa prefers cooler weather, so the best time of year to plant seeds is in the spring. If you live in a warmer climate, you would benefit from fall planting. Choose and prepare an area in full sun. Clear away debris and work the dirt after the last frost in the spring. Alfalfa prefers well-drained soil with a neutral pH. When growing it as green manure, you could easily plant it in raised beds. However, larger garden areas are more suitable for growing alfalfa.
Once the ground is ready, sow seeds by sprinkling them over the dirt and use a rake to cover them lightly; they will germinate within 7 days. Alfalfa can also be propagated by cuttings if you have access to an existing field. Below, we will discuss in greater detail the steps to growing alfalfa from seed and also how to grow from stem cuttings.
Let’s take an in-depth look at the specific care required to grow alfalfa. Light, temperature, water, and fertilizer are important factors to consider so you can achieve a healthy yield.
Sun and Temperature
Alfalfa requires direct sunlight, meaning it needs at least 6-8 hours of sun per day for optimal growth. It thrives in USDA growing zones 2-9, thus it will tolerate a variety of environments from cooler temperatures to heat. Mature plants will do better once the weather turns hot, which is why you want to plant them in the cool season.
It can withstand a light freeze if you’ve planted it early in the spring or a little late in the fall. Alfalfa has a good cold tolerance but the leaves and buds can become damaged by the frost. Special protection from the cold is unnecessary as alfalfa stands go dormant in the winter after harvesting once the temperatures drop below 20F.
Water and Humidity
Provide enough water to keep the ground moist but not soggy. Alfalfa is drought tolerant and prefers a dry ground surface over water-logged, but grows the best with a consistent supply of moisture. Watering from ground level is ideal for keeping the leaves from getting wet, which prevents less chance of fungal issues. If watering with sprinklers, do this in the morning so the leaves have time to dry during the heat of the day. There’s no need to water alfalfa during the winter when it is dormant, as it doesn’t require extra moisture.
Alfalfa does not like to grow in rocky or eroded soil. It prefers well-draining loam soil comprising silt, sand, and/or clay with a neutral pH range at approximately 6.6-7.0; if you have acidic soil, then alfalfa will not thrive unless you neutralize the pH by adding lime.
To fertilize alfalfa, provide extra nitrogen or add organic matter (especially to coarse-textured soil) when first planting your alfalfa. Adding potassium and phosphorus during the growing season will increase yield which is important if you are growing alfalfa hay for animals. Some research shows if you fertilize before the plants go dormant, it will prevent winter kill. At the very least, soil test periodically to check nutrient levels as you may already have high amounts of potassium or phosphorus present.
Alfalfa doesn’t have to be pruned in the same sense of pruning a rose bush. Once it blooms, you have the option to cut and drop. This means you cut the alfalfa and leave the cut stems and leaves on the ground to decompose. The fallen plant material is a great way to amend your soil if you aren’t planning to use the cut alfalfa for other reasons (such as for livestock feed).
Growing alfalfa from seed is the most common method since most farmers grow at least an acre. In the spring, prepare the soil once the danger of frost has passed. If using it for a cover crop, plant the alfalfa seeds in the fall. You can buy seeds inoculated with rhizobium bacteria, which helps fix nitrogen in the soil.
Sow seeds by sprinkling them on a well-prepared seedbed and then using a rake to lightly cover them with soil. Keep the soil moist until the seeds have germinated, which takes 7-10 days. Thin the alfalfa seedlings to approximately 6 inches of space between each plant to allow for airflow as it matures.
Cuttings are an option if you have an existing patch you want to expand or you have a small area you want to grow alfalfa in. Gather cuttings in the spring so they have time to root before the weather turns cold.
Select healthy plants at least 6 inches tall and trim the stem close to the ground. Strip the lower leaves from the stem, leaving at least 3 top leaves. Place the stem in water to rest overnight. The next day, place the bottom 1.5-2 inches of the stem into a shallow container filled with moist soil. Space each cutting 3-4 inches apart. Provide plenty of light and keep the soil moist, but not soggy. Within 6 weeks, roots will have formed and they are ready to transplant to the prepared garden area.
Alfalfa isn’t afflicted with many pests and diseases compared to other plants that home gardeners grow. However, it is good to be aware of potential problems so you can take care of them quickly before too much damage has occurred.
Since alfalfa has a deep taproot, it is inadvisable to grow where any lingering chemicals have been sprayed within the last 2 years. Neutral soil pH is also important when growing healthy alfalfa, as it can more easily resist diseases and pests and not require pesticide spray.
Alfalfa can house many insects, though most of them are beneficial. There are a few to be aware of that can cause havoc, and they are alfalfa weevils, aphids, and blister beetles.
Aphids are a common pest that is well known by gardeners, and there are more than one species that will feast on alfalfa. They are tiny, oval-shaped, and can be bright green, tan, yellow, or dark brown. Damage from these pests can cause stunted growth, mottled and/or curled leaves. Some varieties are resistant to aphids and keeping your patch healthy will help fight an infestation naturally. Encourage beneficial pests such as ladybugs, lacewings, or predatory beetles to take residence to keep the aphid population down too. Neem oil applied in the late afternoon once pollinators have retreated will take out the aphids.
The alfalfa weevil is light brown with a dark stripe along its back. Adults and larvae feed on the alfalfa leaves, which can delay the growth of the plant and reduce overall yield. Insecticide is not recommended to use during the day when the alfalfa is flowering because it can kill pollinators while wet; apply an organic option like pyrethrin in the late afternoon or early evening once pollinators have retreated for the day. Harvest early to lessen the damage and consider using natural predators of the weevil such as parasitic wasps.
Blister beetles don’t affect the crop itself, but if you are using alfalfa as a forage crop, it’s good to know that they are toxic to horses if they eat this insect when grazing. It’s easy to identify blister beetles because they are large, with elongated black bodies, broad heads, and long antennae. The beetles are attracted to grasshoppers and flowering alfalfa. Chemical control won’t help as their toxin is still present in the beetle bodies after they are dead. If found, it may be best to avoid using this as fodder.
The two most common diseases that affect alfalfa are leaf spots and crown rot. Generally, it’s a vigorous plant, but it’s good to be aware of infections that could affect your crop.
Common leaf spot (Pseudopeziza medicaginis), is a fungal infection also known as alfalfa leaf spot. This fungus prefers cool and moist conditions and acidic soil. You won’t see this disease as often in the southern warmer states. If you live in an area that receives a lot of rain, the chances for this pathogen to attack increase dramatically.
There are some varieties of alfalfa that are more resistant to common leaf spot, though no variety exists that is fully resistant. Fungicides are not always effective, so if you notice this disease early, it is best to harvest your crop before it spreads. An application of copper fungicide may slow the spread. Signs of leaf spot are circular brown spots on the leaves starting near the bottom of the plant that works their way up to the older leaves. These eventually shrivel and fall from the plant.
The second most common disease is root and crown rot caused by Phytophthora fungus. The fungi live in the soil and can spread to other plants through irrigation water. Affected plants will eventually die, but the disease starts in the taproot and spreads upward. The first signs will be brown lesions present on the taproot.
The best form of management is to provide ideal conditions during the growing season. Plant alfalfa in well-drained soil, prevent soil compaction, over-watering, and avert injury to your crop from nematodes and other pests. Fortunately, there are varieties that are resistant to this fungal infection.
Frequently Asked Questions
Q: How long does it take to grow alfalfa?
A: With the best conditions, the first cutting of alfalfa would be ready in approximately 40 days from when the seeds germinate; when the alfalfa stands at least 15 inches tall.
Q: Does alfalfa grow back every year?
A: Yes, alfalfa is a perennial and will grow back every year as long as it receives the proper care. Overall, it is an easy crop to grow.
Q: What month do you plant alfalfa?
A: Plant alfalfa after the danger of frost has passed in your area, usually by April or May. If you live in a warmer climate, plant alfalfa in the fall, September to November, as it is a cool-season crop. Very warm zones that rarely drop below freezing may be able to start a late winter crop for mid-spring harvest if desired.
Q: How profitable is growing alfalfa?
A: It depends on how large of an area you plan to cultivate and what you plan to do with the alfalfa once you have grown it. A small garden plot would not be beneficial, but with careful planning, you could profit from at least an acre of quality alfalfa hay.
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