Rhubarb, with its vibrant crimson stalks and tart flavor, is a beloved harbinger of spring for many gardeners. Forcing rhubarb, a technique that encourages early growth, allows you to harvest those delicious stalks weeks, even months, ahead of the natural season. But knowing exactly when to remove your rhubarb forcer is crucial for both maximizing your harvest and ensuring the long-term health and productivity of your plant. Understanding the nuances of forcing and the signs your rhubarb is ready is key to a successful early crop.
Understanding Rhubarb Forcing: The Basics
Forcing rhubarb mimics an early spring by manipulating the plant’s environment. By excluding light and providing gentle warmth, we trick the rhubarb into breaking dormancy and pushing up stalks prematurely. This results in tender, sweeter stalks that are highly prized. But to fully grasp when to remove the forcer, we need to delve deeper into the process.
Why Force Rhubarb?
The primary reason for forcing rhubarb is to obtain an early harvest. The stalks produced under forcing conditions are typically more tender and less stringy than those grown naturally. The lack of light inhibits chlorophyll production, resulting in a paler color and a sweeter, milder flavor. For many gardeners, this early yield is a welcome taste of spring after a long winter.
How Rhubarb Forcing Works
Rhubarb plants require a period of cold dormancy to build up the energy reserves needed for vigorous growth. Forcing exploits this by creating an artificial spring environment. A forcer, which can be a specialized terracotta pot, a bucket, or even a makeshift structure covered in dark material, blocks out all light. The darkness, coupled with a slightly warmer temperature, encourages the plant to expend its stored energy reserves on producing stalks. This is why it’s essential that the plant is well established before forcing. Forcing relies on these energy reserves, and over-forcing or forcing young plants can weaken them.
Choosing the Right Rhubarb Variety for Forcing
While most rhubarb varieties can be forced, some are better suited to the process than others. ‘Timperley Early’ is a popular choice, as its name suggests, being specifically bred for early forcing. Other varieties like ‘Victoria’ can also be successfully forced, but may not be as naturally predisposed to early growth. Consider your local climate and the varieties that thrive in your region when making your selection. Seed catalogs and local nurseries are valuable resources for determining the best varieties for your specific needs.
Recognizing the Signs: When to Remove the Forcer
Knowing when to remove the rhubarb forcer is not an exact science; it depends on several factors, including the variety of rhubarb, the weather conditions, and your personal preferences. However, there are key signs to look for that indicate your rhubarb is ready for harvest and the forcer can be removed.
The Ideal Stalk Length
One of the most obvious indicators is the length of the stalks. Generally, stalks that are 12-18 inches long are considered ready for harvesting. While you can harvest stalks that are slightly shorter, they may not be as fully developed in terms of flavor and texture. Stalks significantly longer than 18 inches may become tougher and more stringy, diminishing their quality.
The Color of the Stalks
While forced rhubarb will be paler than naturally grown rhubarb, the color of the stalks still provides a clue. Look for a vibrant pink or red hue in the stalks, indicating they are nearing maturity. Avoid harvesting stalks that are still predominantly green or appear weak and spindly. These may not have fully developed their flavor.
The Condition of the Leaves
The leaves of forced rhubarb will be smaller and less robust than those grown naturally. While the leaves themselves are not edible due to their high oxalic acid content, their condition can indicate the overall health of the plant and the progress of the forcing process. If the leaves appear healthy and the stalks are of the appropriate length and color, it’s a good sign that the forcer can be removed.
Timing and Weather Considerations
Timing is everything. Typically, forced rhubarb is ready for harvest 4-8 weeks after the forcer is put in place. This timeframe can vary depending on the weather. Warmer temperatures will accelerate growth, while colder temperatures will slow it down. Keep a close eye on the rhubarb’s progress, especially during periods of fluctuating temperatures. Consider starting forcing in late winter/early spring when the plant is still dormant, but the weather is beginning to warm up. This will give you the best chance of an early harvest.
The “Pull Test”
A simple but effective method for assessing readiness is the “pull test.” Gently grasp a stalk near the base and pull it away from the plant with a slight twisting motion. If the stalk comes away easily, it’s ready for harvesting. If it requires significant force, it’s likely not quite mature enough and should be left for a few more days. This is a good way to confirm your visual assessment.
Removing the Forcer: Best Practices
Removing the forcer is a simple process, but it’s important to do it carefully to minimize stress on the plant.
Gentle Handling
When removing the forcer, be gentle to avoid damaging the delicate stalks. If you’re using a heavy terracotta pot, consider having someone help you lift it. Avoid yanking or forcing the forcer off the plant, as this could break the stalks or damage the crown.
Harvesting the Stalks
Once the forcer is removed, harvest the ripe stalks immediately. This will encourage the plant to produce more stalks. To harvest, grasp the stalk near the base and pull it away from the plant with a slight twisting motion. Avoid cutting the stalks, as this can leave the plant vulnerable to disease. Leave a few stalks to continue growing and nourish the plant. Don’t harvest all the stalks at once.
Post-Forcing Care
After harvesting, the rhubarb plant will be somewhat depleted of energy. It’s important to provide it with some post-forcing care to help it recover.
Fertilizing the Plant
Apply a balanced fertilizer to replenish the nutrients lost during the forcing process. A fertilizer high in phosphorus and potassium will promote strong root growth and overall plant health. Follow the manufacturer’s instructions carefully to avoid over-fertilizing.
Watering and Mulching
Ensure the plant receives adequate water, especially during dry periods. Mulching around the base of the plant will help to retain moisture and suppress weeds. Organic mulches, such as compost or well-rotted manure, will also provide additional nutrients to the soil.
Allowing the Plant to Recover
It’s crucial to allow the rhubarb plant to recover fully after forcing. Avoid forcing the same plant for consecutive years, as this can weaken it over time. Allow at least one year of unforced growth between forcing sessions. During this time, the plant will rebuild its energy reserves and prepare for future growth. Resist the temptation to harvest too many stalks from unforced plants as well.
Troubleshooting Common Issues
Even with careful planning, some issues can arise during the rhubarb forcing process. Recognizing and addressing these problems promptly can help ensure a successful harvest.
Stunted Growth
If the stalks are growing very slowly or not at all, it could be due to several factors. The plant may not have been sufficiently chilled during dormancy, or the temperature inside the forcer may be too cold. Ensure the plant has experienced a period of cold dormancy before forcing, and provide some insulation if the weather is particularly cold. Another possibility is that the plant is simply not strong enough to support forced growth. This could be due to over-forcing in previous years or inadequate fertilization.
Mold or Rot
Excess moisture inside the forcer can create a breeding ground for mold and rot. Ensure there is adequate ventilation to prevent moisture buildup. If you notice mold or rot, remove the affected stalks immediately and improve air circulation around the plant. Avoid overwatering, especially during periods of cool, damp weather.
Pest Infestations
While less common during forcing due to the enclosed environment, pests can still occasionally be a problem. Check the plants regularly for signs of pests, such as aphids or slugs. If you find any pests, treat them with an appropriate organic insecticide or slug bait.
Long-Term Rhubarb Care
Rhubarb is a relatively low-maintenance plant, but providing proper care will ensure its long-term health and productivity.
Regular Fertilizing
Fertilize rhubarb annually in the spring with a balanced fertilizer. Avoid over-fertilizing, as this can lead to excessive leaf growth at the expense of stalk production.
Weed Control
Keep the area around the rhubarb plant free of weeds. Weeds compete with the rhubarb for nutrients and water. Mulching can help to suppress weed growth.
Dividing Established Plants
Every few years, divide established rhubarb plants to rejuvenate them and prevent overcrowding. This is best done in the early spring or late fall when the plant is dormant. Dividing involves digging up the plant and separating the crown into smaller sections, each with its own roots and buds. Replant these sections in well-prepared soil.
Protecting from Pests and Diseases
Monitor the rhubarb plant regularly for signs of pests and diseases. Common pests include rhubarb curculio and slugs. Diseases include crown rot and leaf spot. Treat any problems promptly with appropriate organic or chemical controls.
Knowing when to remove your rhubarb forcer is a vital part of successful rhubarb cultivation. Careful observation, understanding the plant’s needs, and providing proper post-forcing care will result in a bountiful harvest of delicious, early-season rhubarb for years to come. Remember, patience and attention to detail are key to unlocking the secrets of forcing this rewarding garden staple.
When is the ideal time to remove my rhubarb forcer?
The ideal time to remove your rhubarb forcer is typically when the stalks reach 12-18 inches in height and the leaves are just beginning to unfurl. This usually coincides with late spring or early summer, depending on your local climate and the specific variety of rhubarb you are forcing. Monitor the growth closely, as you want to harvest the forced rhubarb while it’s still tender and before it becomes too stringy.
Removing the forcer too early can expose the delicate, pale stalks to sudden changes in temperature and sunlight, potentially damaging them. Leaving it on too long can result in the stalks becoming overcrowded and less tender. Observe the plant regularly, and once the stalks have reached the desired size and the leaves are starting to open, it’s the perfect time to lift the forcer and enjoy your harvest.
How do I remove the rhubarb forcer without damaging the plant?
Gently lift the rhubarb forcer straight up, taking care not to disturb the surrounding soil or break any of the stalks. If the forcer is heavy or difficult to maneuver, consider asking someone for assistance. Avoid twisting or pulling the forcer, as this could damage the crown of the plant and hinder future growth.
Once the forcer is removed, you may want to lightly mulch around the base of the rhubarb plant to help retain moisture and suppress weeds. Be sure to inspect the harvested stalks for any signs of pests or diseases. Properly cleaned and stored, your rhubarb forcer will be ready to use again next year for another bountiful harvest.
What happens if I leave the forcer on for too long?
If you leave the rhubarb forcer on for too long, the stalks will continue to grow taller and thicker, but they will lose their tender texture and become stringier. The leaves will also expand and become tougher, making them less palatable. While the rhubarb will still be edible, the quality will be significantly diminished.
Furthermore, overcrowding within the forcer can limit air circulation, increasing the risk of fungal diseases. The plant might also become stressed, potentially affecting its overall health and future productivity. It’s best to remove the forcer when the stalks are at their peak tenderness to ensure the best possible flavor and texture.
Can I use the rhubarb forcer on the same plant every year?
Yes, you can definitely use the rhubarb forcer on the same plant year after year, but it’s crucial to allow the plant to recover and build up its energy reserves after forcing. Forcing rhubarb puts a strain on the plant, so it needs time to replenish its nutrients for optimal future growth and production.
After harvesting the forced rhubarb, allow the plant to grow naturally for the rest of the season. This allows the plant to photosynthesize and store energy in its roots. You can then force the same plant again the following year, or alternate between plants to further minimize stress and ensure consistent yields. Regular feeding and watering will also help maintain the plant’s health.
What if I see small shoots starting to appear outside the forcer?
If you notice small shoots starting to appear outside the rhubarb forcer, this indicates that the plant is actively growing and ready to be forced. These shoots are a sign that the plant has broken dormancy and is responding to the warmer temperatures and increased light levels inside the forcer.
This is a good time to check the overall progress of the stalks inside the forcer. If they are close to the desired height (12-18 inches) and the leaves are starting to unfurl, you can remove the forcer within a few days. If the stalks are still too small, give them a little more time to grow, but keep a close eye on them to prevent them from becoming overgrown.
What do I do with the forced rhubarb after removing the forcer?
After removing the forcer and harvesting your forced rhubarb, it’s time to enjoy your delicious crop! The stalks should be used as soon as possible for the best flavor and texture. You can store them in the refrigerator for a few days, but they are best when fresh.
Forced rhubarb is incredibly versatile and can be used in a variety of culinary applications, such as pies, crumbles, jams, and sauces. Remember that only the stalks are edible, and the leaves are toxic and should be discarded. Prepare your rhubarb according to your favorite recipe and savor the unique, delicate flavor of forced rhubarb.
How do I care for the rhubarb plant after removing the forcer?
After removing the rhubarb forcer and harvesting the forced stalks, it’s important to care for the plant to ensure its continued health and productivity. Water the plant deeply, especially during dry periods. This will help it recover from the energy expenditure of forcing.
You can also apply a balanced fertilizer to replenish the nutrients in the soil. Remove any dead or damaged leaves to improve air circulation and prevent disease. Allowing the plant to grow naturally for the rest of the season will help it build up energy reserves for future harvests, whether forced or unforced. Regular monitoring for pests and diseases is also crucial to maintaining a healthy rhubarb plant.