A Grower’s Guide To Raspberry Companion Planting
Growing raspberries can be a rewarding experience. Raspberries never seem to last long when you buy them at the grocery store, and they never taste as good as freshly-picked berries. So how do you grow raspberries?
Raspberries require well-drained, slightly acidic soil.
Fertilize them with a good blend of Nitrogen, Phosphorous, and Potassium to ensure healthy growth. Raspberries need full sun in a region with mild winters and cooler summers. Pair raspberries with companion plants that help suppress weeds and retain moisture.
Published: October 31, 2022.
New and old gardeners learn new things about growing their plants by experimenting in their gardens and reading about the successes and failures of others. In this article, we will cover everything you need to know to achieve a successful raspberry harvest.
In What Type Of Soil Do Raspberries Grow Best?
Raspberries prefer soil with plenty of organic material that keeps the dirt from becoming too compact. The roots of raspberries also do not like wet feet, so it is best to plant them someplace that drains well and where the soil does not stay overly moist.
Plant raspberries in a place where they can be irrigated. In dry summers, it is necessary to water the raspberries. As long as the plants receive a sufficient amount of water leading up to harvest time, the raspberry yield should be good.
How Do I Get My Soil Ready To Grow Raspberries?
Gardeners can either plant raspberries in raised garden beds or directly into the ground. When planting into a raised bed, mix soil and compost for rich, loamy soil. In raised beds, it is easier to prevent wet feet; however, the plants will likely need irrigation.
When planting directly into the ground, the bed area should be prepared using a method that allows organic materials to be mixed into the soil layers where the roots grow. This can be done using a tiller or a no-till method.
Many farmers, especially organic farmers, have switched to using no-till methods in their gardens. This method naturally increases the organic material in the soil over time and boosts the soil's life, which helps the growth of the plants.
Farmers or gardeners who want to use a no-till method can start by planting a cover crop that returns nutrients to the soil, such as vetch or clover. Before planting, use a broad fork to break up the soil compaction and mix it with some compost.
What is the Optimal pH for Raspberry Growth?
Raspberry plants really like to grow in soil that is slightly acidic or with a pH between 5.6 to 6.5 (these numbers may vary slightly depending on variety). Always test your soil before planting. Your local county extension can help you find a place to test it.
If your soil is too acidic and you need to increase the pH, add ground limestone. If the soil pH is too high, adding compost and manure will help lower the soil pH. Once the soil pH is within the ideal range, you are halfway to successfully growing raspberries.
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What Minerals and Nutrients Do Raspberries Need?
Raspberries need a good balance of nutrients to grow.
Testing your soil will tell you what nutrient deficiencies exist and what fertilizers you need to promote good growth.
Applying a balanced fertilizer with Nitrogen, Phosphorus, and Potassium (NPK) is usually recommended once the raspberry plants are established.
Gardeners should be careful not to add too much, which risks burning the plant and potentially killing it.
Many NPK fertilizer mixes are available at lawn and garden stores. These can be organic fertilizers that come from natural sources or non-organic, meaning they are derived from a chemical process.
These fertilizer mixes come in various formulations. For raspberries, 10-10-10 or 5-10-5 are often recommended. The first number refers to the amount of Nitrogen (N), the second is Phosphorous (P), and the third is Potassium (K).
The numbers in the formulation refer to the amount of each element with respect to the others. Additional nutrients can be added to your raspberries through the use of bone meal, blood meal, fish meal, organic compost, worm castings and other organic fertilizers.
In addition to the general dosing of NPK, gardeners should also be aware of the micronutrients in their soil that are necessary for a healthy plant.
Iron and magnesium deficiencies can cause the plant to be unhealthy, which would reduce production.
Signs of a Mineral Deficiency
When raspberries lack a sufficient amount of phosphorus, the small twigs that shoot off of the canes are very thin. In addition, the leaves grow out small. These signs indicate that the berry production of the canes will be low.
An iron deficiency is characterized by yellow leaves with green striping, while brown edges on the leaves are a potassium deficiency. Weak leaf growth and yellowed leaves show a deficiency of nitrogen and magnesium.
Gardeners should pay attention to how well the raspberry canes grow.
Poor or slow growth can indicate that adding fertilizer to the soil around the plants is necessary to boost growth. When raspberry plants shoot out a lot of green growth, it indicates that they are well-fertilized.
How Much Sun Do Raspberries Need?
Raspberries need full sun for six to eight hours over many days, not necessarily consecutive, for successful growth. This sunlight is essential to achieve productive raspberry canes, no matter which type of raspberry you are growing.
Two types of raspberries, primocane-bearing, and floricane-bearing, are available to gardeners. Primocane-bearing raspberries grow on the canes that grew in the current year, while floricane-bearing raspberries grow on the previous year’s canes.
Primocane raspberries are easier to manage than floricane-bearing raspberries. Their canes can be chopped down at the end of the growing season and do not require as much trellising as floricane raspberries.
Some of the cultivars of both types of raspberries yield multiple harvests from the same plant each year, one in the summer and again in the fall.
To achieve a second harvest, the raspberry plants need sufficient sun and nutrition to maintain good health.
Where do Raspberries Grow Best?
Raspberries grow best in places that have mild winters and cool summers. According to the US Department of Agriculture (USDA) Plant Hardiness Zone Map, raspberries generally do well between zones 3 and 9.
Farmers outside of these zones can successfully produce raspberries, but they have to work harder. Your growing season can be extended in northern climes by using a greenhouse to prevent an early frost from killing the raspberry plants.
How To Select The Right Raspberries for My Location?
All of the different cultivars have a preferred location where they grow well and yield good berry harvests. Gardeners have several tools available that they can use to determine which cultivars will work best in their zone.
Farmers and gardeners can find their zone by typing their zip codes into the USDA’s Plant Hardiness Zone Map. After finding your zone, shopping for raspberry cultivars is easy. Many online plant nurseries provide a zone guide for each plant they sell.
Plants purchased at local nurseries are always a safe purchase too. The raspberry varieties grown by your local nurseries have already demonstrated their hardiness for the zone where you live.
Gardeners should first decide which type of raspberry they want to grow, primocane or floricane, and then choose the raspberry cultivar that fits their needs. Many raspberry varieties grow red berries, but some produce yellow, black, and purple.
At What Temperature Do Raspberries Grow Best?
Raspberry cultivars can grow in a wide range of temperatures. Some varieties perform better in more northern parts of the United States, while others do well in the southern states because they can not survive over winter.
Some raspberry cultivars are more disease resistant than others. The varieties that succumb more easily to things like rots and blights should be grown in conditions that are warm and dry because cool and moist conditions provide opportunities for these diseases to take hold.
Raspberries can suffer from fungal, bacterial, and viral diseases. If you notice anything unhealthy about your raspberry plants, it is important to act quickly to try to save them. Some diseases that infect raspberries include:
- Botrytis Fruit Rot
- Gray Mold Wilt
- Cane Blight
- Spur Blight
- Powdery Mildew
- Fire Blight
- Root Rot
- Bacterial Blight
Removing all canes that look like they have been touched with blight, mildew, or rot is important. Take care not to let the infected canes or leaves touch the healthy canes. Dispose of the infected canes away from the healthy plants.
To prevent a reoccurrence of mildew, rot, blight, or wilt, gardeners should prune often and check the growing conditions of their raspberries.
If plants are receiving too much water, are located in a very humid area, or have poor air circulation, the plants are at risk of contracting a disease.
What Plants Make Good Companion Plants for Raspberries?
So given all of these requirements in soil, pH, sun, nutrients, location, and temperature, what plants make good companions for raspberries?
Companion plants can serve different purposes. Some can deter pests, while others can provide nutrients. Companion plants should not be overly competitive with the raspberries for space, water, or nutrition.
Alliums are great companion plants for raspberries. They do not compete for root space, and they help deter animals such as deer and rabbits. The alliums that make good companion plants include:
Many herbs make great companion plants for raspberries, especially those that cover the soil without competing for root space or nutrition. By covering the soil, they make it more difficult for weeds to grow. Good herbal companions for raspberries include:
Legumes are nitrogen fixers. They take in nitrogen from the atmosphere and convert it into a form other plants can use.
These plants boost nitrogen in the soil, which helps all of the other plants around them. Legumes that make great companion plants for raspberries include:
Some flower species attract excellent pollinators that can help boost plant productivity. In addition, some of these flowers promote excellent health in a garden by repelling pest bugs and attracting insects that prey on pest bugs that damage crops like raspberries.
Great flowering companions for raspberries include:
Turnips are also a great companion for raspberries. They do not compete with raspberries for root space or above-ground space. In addition, they repel a voracious raspberry pest, the harlequin beetle.
Some gardeners warn people not to grow strawberries with raspberries, while others say it is a great idea. Growing strawberries with raspberries can be a problem if the strawberries carry a contagious disease that can infect the raspberry plants.
However, gardeners who select raspberry cultivars that are resistant to wilts, rots, and blights can likely plant strawberries and raspberries together without any problems.
This idea generally does not apply to companion planting with plants in the Nightshade family.
Raspberries and strawberries can make excellent companion plants because the roots of strawberries are shallow, while those of the raspberries are deeper.
Gardeners can make use of these different ways of growing to cut down on weed growth in their berry beds.
What Plants Should You Avoid Planting Near Raspberries?
Some plants do not make good companions for raspberries because they tend to carry diseases that can infect them.
Plants in the Nightshade family are notorious for carrying diseases that infect raspberries. These bad companion plants include:
- Goji Berries
Not only are these plants bad companions, but raspberries also should not be planted in a bed that has contained a Nightshade species within the last five years.
The fungus, Verticillium Wilt, is contagious and persists in the soil long after the plants that carried it have died.
Gardeners should plant raspberries in acidic soils that contain organic matter and a good balance of Nitrogen, Phosphorous, and Potassium. Raspberries need full sun for six to eight hours and grow well in zones 3 to 9.
The best companion plants for raspberries include onions, chives, borage, chamomile, basil, and peas.
The worst plants to plant near raspberries are tomatoes, potatoes, peppers, and eggplant.