The Best Organic Fertilizer for Rhubarb – A Complete Guide
This plant can survive in cold weather and grows tasty stalks that can be used in pies, jams, and other recipes. Rhubarb is simple to grow, but it needs extra food to give you the best harvest. The key to success is to use an organic fertilizer that is made for rhubarb. We’ll talk about everything you need to know about organically feeding rhubarb in this guide.
What Does Rhubarb Need Nutritionally?
Rhubarb has pretty high nutritional demands compared to other garden plants. It is a heavy feeder that rapidly depletes nitrogen reserves in the soil. Rhubarb also needs adequate levels of phosphorus and potassium for optimal growth. The ideal fertilizer for rhubarb has an NPK ratio around 10-10-10. This provides a balance of primary macronutrients. Secondary nutrients like calcium magnesium, and sulfur are also beneficial.
When Should I Fertilize My Rhubarb?
Timing is important when fertilizing rhubarb. In early spring, when the buds start to get bigger, the plant needs a good nutrition boost. This ensures strong growth and stalk production. You can apply it again in the middle of the season if plants show signs of not getting enough nutrients. Do not fertilize rhubarb in late summer or fall, as this can make it less hardy in the winter.
How Frequently Should I Fertilize Rhubarb?
One heavy spring feeding is sufficient in most cases. However, rhubarb grown in sandy or nutritionally deficient soils may need a second application later in the growing season. As a general rule, established rhubarb plants should be fertilized once or twice per year. Newly planted rhubarb should not be fertilized for the first year after transplanting.
What is the Best Organic Fertilizer for Rhubarb?
There are lots of excellent organic fertilizer choices for rhubarb:
-
Compost and composted manure provide a slow-release feeding of nitrogen, phosphorus, potassium and micronutrients.
-
Fish emulsion is a fast-acting organic nitrogen source that gives plants a quick boost.
-
Bone meal and rock phosphate are natural sources of phosphorus.
-
Kelp meal adds potassium, micronutrients and beneficial compounds.
-
Organic all-purpose fertilizers blended specifically for fruit and vegetables.
For best results, use a combination of fast- and slow-release organic fertilizers. This provides both an immediate nutrient infusion and longer-term feeding.
How Should I Apply Organic Fertilizer to Rhubarb?
Organic fertilizers can be applied in several ways:
-
Granular fertilizer should be spread around the base of plants, being careful not to touch the leaves directly.
-
Dig fertilizer into the soil around plants to a depth of 8-12 inches.
-
Create a trench around plants and bury fertilizer 6 inches deep.
-
Mix water-soluble fertilizers like fish emulsion into water and apply directly to soil.
Always follow label directions for correct application rates and methods. After using fertilizer, water the plants well to get the nutrients into the root zone.
Tips for Using Organic Fertilizers Effectively
Here are some useful tips for getting great results from organic fertilizers:
-
Test your soil to identify any nutritional deficiencies before applying fertilizer.
-
Combine fast-acting and slow-release fertilizers to get both quick and longer-term feeding.
-
Rotate fertilizers annually to provide a wider spectrum of nutrients over time.
-
Apply 1-2 pounds of 10-10-10 organic fertilizer per 100 square feet of rhubarb.
-
Replenish the soil with compost or manure every 2-3 years.
-
Side dress with extra nitrogen if growth seems weak midseason.
-
Always follow label instructions carefully to avoid over-fertilization.
The Importance of Proper Soil pH for Rhubarb
Rhubarb does best in slightly acidic soil with a pH between 6.0-6.8. Adding lime raises pH, while sulfur can be used to lower pH. Test soil pH annually and adjust as needed. Proper pH ensures rhubarb can access nutrients from organic fertilizers.
Over-Fertilization of Rhubarb Must Be Avoided
It’s easy to overdo it with fertilizer, but this can damage rhubarb plants. Signs of over-fertilization include:
-
Excessive leafy growth with fewer stalks.
-
Burnt leaf tips or margins.
-
Stunted roots and poor winter survival.
-
Increased vulnerability to pests and diseases.
Go easy on fertilizer rates and always water it in thoroughly. It’s better to under-fertilize than overdo it.
Organic Rhubarb Fertilization Schedule
Here is a sample fertilization schedule for rhubarb using organic fertilizers:
Spring:
-
Early spring – compost/manure + all-purpose organic fertilizer
-
Mid spring – fish emulsion or fast-acting nitrogen
Summer:
- Side dress with compost/manure if plants are struggling
Fall:
- Late fall – apply rock phosphate or bone meal
By following this schedule, your rhubarb will get the steady nutrient feeding it needs for optimal stalk production. Adjust specifics based on your soil, climate and observed plant growth.
The Bottom Line
Providing balanced organic nutrition tailored to rhubarb’s needs is the secret to a plentiful harvest. Aim for an NPK ratio around 10-10-10 applied in early spring and summer. Combine fast-acting and slow-release organic fertilizers for the best results. With the right fertilization program, your rhubarb will produce bumper crops of tasty stalks year after year.
Soil pH and fertility
- The best soil for rhubarb is well-drained.
- Loamy soils are better for rhubarb growth than sandy soils. They hold on to water better and can give plants more nutrients.
- Soil pH is not important. Minnesota garden soil can grow a good crop of rhubarb, no matter how acidic, neutral, or basic (alkaline) it is. Soil tests from parts of the garden where annual plants are grown won’t tell you what the rhubarb plant needs because they are from those areas.
- The rhubarb plant is a “heavy feeder. To make its big stalks and leaves, the plant needs to take in a lot of nutrients from the soil.
- You should add either a balanced commercial fertilizer or rich compost to the soil once a year, or both. Micronutrients and organic matter can be added to soil by adding manure or compost. Write down whether the growth is strong or weak, and then change how much fertilizer you use next spring based on that information.
- Phosphorus builds up in the soil when high-phosphorus fertilizers like 10-10-10 or 15-30-15 are used over and over again, or when a lot of manure or manure compost is used. Some runoff may occur with phosphate fertilizer. Then it can become a big problem for polluting our lakes, rivers, and streams. Too much algae grows when there is a lot of phosphorus in the water, which makes the water quality much worse.
- Check to see if your soil has a lot of phosphorus. If it does, use a fertilizer with little or no phosphorus, like 32-3-10, 27-3-3, or 25-3-12.
Gardeners often acquire rhubarb plants from another gardener who is dividing a large plant. Although there is a possibility of receiving a plant infected with a virus, chances are good that the plant is healthy and vigorous, since it is large enough to need dividing.
You can also purchase plants at garden centers and from mail-order catalogs. Nursery-grown plants will be virus-free.
Catalogs also sell rhubarb seed. The reddest varieties are not available as seed, only as plants.
- Different varieties have varying levels of sourness and fibrousness.
- The color of the different types ranges from almost pure green to almost pure red. The skin is mostly red, and the flesh is a range of shades of green, from light to dark.
- Color does not cause any specific flavors. For pies, redder varieties are better because the filling looks better than cooked green varieties, which are a grayish color.
- Plant stature and vigor also vary among varieties. Most of the time, green varieties are stronger and have longer stalks than red varieties.
- Rhubarb leaves are toxic. Do not eat them.
- Only the long, thick leaf petioles, the “stalks,” are edible. There is a lot of oxalic acid in the stalks, which can bind calcium and stop the body from using it.
- Eating a dish with rhubarb every once in a while is not likely to hurt your health.
- People with rheumatoid arthritis, gout, or kidney problems may want to stay away from foods that are high in oxalic acid. They should also talk to their doctors before eating these foods.
How To Feed Rhubarb For Larger Yields!
FAQ
What is the best thing to feed rhubarb with?
Garden compost and well-rotted manure generally contain low levels of nitrogen, phosphates and potash (NPK).
How do you fertilize rhubarb naturally?
Manure is an extremely valuable source of organic matter, as it helps to conserve moisture, preserves the soil structure and makes nutrients readily available. If you choose to use it for your rhubarb, do not use fresh manure— this could burn the tender plants. Apply one to two shovels of older manure per plant.
Can you put Miracle-Gro on rhubarb?
As a “heavy feeder,” rhubarb does well with a lot of fertilizer. It can be 10-10-10 granules or a water-soluble fertilizer like Miracle Gro. That will help build energy for the plant.
What is the secret to growing rhubarb?
Rhubarb thrives in cool climates and requires a location that receives full sun or partial shade. Choose a spot in your garden that provides at least 6-8 hours of sunlight per day. Ensure that the area has well-drained soil, as rhubarb does not tolerate waterlogged conditions.