Can You Grow Fruit Trees in a Wicking Bed?

While agriculture has been around since the dawn of man, we’ve been looking for new and exciting ways to grow crops. One of those ways, which was invented in our own backyard (not literally) is using wicking beds. But the question is, can you grow fruit trees in wicking beds?

Well, the answer isn’t so straightforward. There are several things to consider, which I’ll cover in this guide. So, if you’re thinking about using this form of a raised bed to grow, say, a citrus tree, I urge you to continue reading!

What Is a Wicking Bed?

If you know what a raised bed is, you partially know what a wicking bed is. Basically, a wicking bed is a raised bed—i.e., a freestanding garden bed constructed above ground level—the roots directly receive water from underneath.

This method of growing crops was introduced by Colin Austin, an Australian inventor, to help farmers where water was scarce. The main idea of wicking beds is to keep water out sunlight, thereby reducing the risk of evaporation. In addition, the water is directed straight to the roots, which reduces waste.

Parts of a Wicking Bed

The main components of a wicking bed are as follows:

• Water Impervious Container: The container holds the water reservoir and is made from a material that prevents water from seeping out, ensuring water is efficiently used by the plants above through capillary action.
• Reservoir Gauge: This feature uses a ping pong ball as a visual indicator of the water level within the reservoir. The ball floats on the water surface, making it easy to see the water level through a clear section of the fill pipe.
• Fill Pipe: This pipe allows for easy filling of the water reservoir below the soil. It’s wide enough to accommodate a hose for quick and efficient refilling.
• Mulch Layer: Placed on top of the soil, this layer helps to reduce evaporation, keep the soil cool, and suppress weed growth.
• Planting Soil: A layer of soil where plants are grown. It is typically rich in nutrients and designed to facilitate good drainage while retaining enough moisture.
• Weedmat: Positioned just below the planting soil, it helps to retain soil and prevent it from mixing into the layer below.
• Bulkhead Drain: A safety feature to drain excess water and prevent the water level from exceeding the maximum, thereby safeguarding against root rot.
• Corrugated Piping: These pipes are part of the system’s foundation, facilitating the distribution and storage of water. They also help in aerating the root zone.
• Fine Sand: This layer sits above the corrugated piping, aiding in the distribution of water upward to the soil through capillary action.
• Sand Column: Acts as a conduit for water moving upwards from the reservoir to the soil, ensuring consistent moisture reaches the roots.

Can You Grow Fruit Trees in a Wicking Bed?

The short and sweet of it is, yes you can. A wicking bed can support growing fruit trees, but there’s one huge caveat: the tree can’t be too large. Basically, any full-sized tree, regardless of the fruit, cannot be sustained in a wicking basket, at least not for the entirety of its lifespan.

Dwarf fruit trees are a completely different story!

As its name suggests, a dwarf fruit tree is a tree that doesn’t grow very tall. It typically reaches a max height of 3.5 meters, but with careful pruning, you can limit its vertical growth by a lot.

You can try experimenting with the following dwarf fruit trees in your wicking bed:

• Apple
• Berries
• Kumquat
• Lemon
• Lime
• Mandarin
• Mulberry
• Orange

Fruit Trees You Cannot Grow in a Wicking Bed

Not all fruit trees, even their dwarf varieties, are suitable for wicking beds. This is mainly due to their deep root systems. Here’s a list you may want to avoid growing in a wicking bed:

• Avocado
• Banana
• Coconut
• Coffee
• Custard Apple
• Lychee
• Macadamia
• Mango
• Pomelo
• Sapote

Tips for Growing Fruit Trees in a Wicking Bed

Growing a miniature fruit tree in a wicking bed can rewarding, especially when done right. Here are a few tips to help you on your journey:

1. Optimize Your Soil Mixture

The soil in a wicking bed should be particularly well-draining yet capable of retaining enough moisture to benefit the tree. A mixture of loamy soil and compost provides both nutrients and proper drainage. Avoid soil that is too dense, as it may retain excessive water and lead to root rot.

2. Regular Pruning and Maintenance

Pruning is done not just to maintain the tree’s size but also boost fruit production. Regular pruning helps to manage the growth of the tree, ensures adequate air circulation, and allows sunlight to penetrate the canopy.

3. Monitor Water Levels Closely

Although wicking beds are designed to reduce watering frequency, you still need to keep a watchful eye on the water level. Make sure the reservoir has plenty of water (excess will spill out through the drain port). Do not leave a running hose in the fill pipe as too much water can misshapen the weedmat and sand layer.

4. Fertilize Appropriately

Fruit trees in wicking beds will benefit from regular feeding, especially during the growing season. Use a balanced, slow-release fertilizer that provides a blend of essential nutrients.

Other Ways to Grow Your Favourite Fruit Trees

Perhaps you don’t feel like pruning your dwarf fruit tree often to minimize its height. No problem, there are several alternatives to wicking beds for growing trees of any size.

1. Traditional Planting in the Ground

For established fruit trees with extensive root systems, planting directly in the ground remains the time-tested and straightforward approach. This method offers several key advantages:

• Unrestricted Growth: Unlike confined spaces in wicking beds, planting in the ground allows unrestricted root development. This freedom enables trees to access a wider range of water and nutrients naturally present in the soil profile.  The unrestricted space promotes healthy root development, leading to better overall growth and fruit production for your tree.
• Reduced Maintenance: Compared to wicking beds, traditional planting requires less ongoing maintenance.  With established roots accessing water and nutrients throughout the soil, the need for frequent watering and monitoring is minimised.  Additionally, there’s no need for specialised construction or repotting as the tree matures.

While traditional planting offers clear benefits, it’s important to consider a few things:

• Space Requirements: Larger fruit tree varieties with sprawling root systems might not be suitable for smaller gardens.  Ensure you have sufficient space to accommodate the mature size of the tree, including its branches, to avoid conflicts with structures or other plantings.
• Initial Effort: While ongoing maintenance is lower, the initial process of planting a fruit tree in the ground can involve more effort. This might include preparing the planting site, amending the soil, and staking the young tree for support until its root system establishes itself.

2. Container Growing with Good Drainage

For those with limited space or who prefer a portable fruit tree solution, container growing with good drainage is a viable alternative to wicking beds. This method offers several advantages:

• Adaptability: A wider range of fruit tree varieties, including some with taproots, can be grown in containers compared to wicking beds.  Remember to choose a pot size appropriate for the mature size of the tree.
• Mobility: Containerized trees offer greater flexibility. You can move them around your patio or verandah to maximise sunlight exposure or protect them from harsh weather conditions.  This is especially beneficial for younger trees or those in regions with unpredictable climates.
• Controlled Environment: Similar to wicking beds, containers provide some control over the growing environment.  By using a well-draining potting mix and providing proper watering and fertilisation, you can ensure your fruit tree receives its specific needs for healthy growth.

However, container growing also comes with some considerations:

• More Frequent Watering: Unlike wicking beds that provide consistent moisture, containerised trees require more frequent watering, especially during hot and dry periods.  Regular monitoring of soil moisture is essential to prevent underwatering or overwatering.
• Repotting Needs: As the tree matures, its root system will expand.  Periodic repotting into a larger container is necessary to accommodate this growth and maintain healthy root development.
• Winter Protection: In colder climates, containerised trees may require additional winter protection to insulate the roots from freezing temperatures.  This might involve wrapping the pot with burlap or placing it in a sheltered location.

3. Planting Bare Root Fruit Trees

For budget-conscious gardeners or those looking for a wider variety selection, planting bare root fruit trees offers a cost-effective alternative. Bare root trees are dormant trees sold without soil around the roots. This method presents both advantages and considerations:

• Cost-Effective: Bare root trees are typically priced lower than containerised trees of the same variety.  This makes them a budget-friendly option for starting your fruit tree orchard.
• Wider Variety: Bare root trees are often available in a wider selection of varieties compared to containerised options.  This allows you to explore more specific fruit types or heritage varieties that might not be readily available in your region.
• Planting Flexibility: The bare root format allows for some flexibility in planting times.  While specific regional recommendations exist, bare root trees can often be planted during the dormant season (late fall or early spring), depending on your climate.

However, planting bare root trees requires more attention to detail compared to other methods:

• Careful Handling: Bare root trees are more susceptible to damage during transportation and planting.  Proper handling and immediate planting upon purchase are crucial for their survival.
• Planting Technique: Planting bare root trees involves careful techniques to ensure proper root placement, root hydration, and initial support. Researching the correct planting method for your specific climate and soil type is essential for successful establishment.
• Initial Care: Newly planted bare root trees require more attention during the first growing season.  Regular watering and monitoring are crucial to ensure their roots establish properly and the tree thrives in its new location.

Ideal Plants for Growing in a Wicking Bed

While wicking beds are a haven for many plants, a select few thrive in these artificial environments.

1. Leafy Greens and Herbs

Leafy greens like lettuce (red leaf, romaine, butter lettuce), spinach, rocket (arugula), and Swiss chard love the readily available moisture zone in a wicking bed. Their shallow root systems thrive in this environment, allowing for continuous harvests throughout the year.

Fragrant and flavorful herbs are another possibility in wicking beds. Basil (sweet basil, Genovese basil, Thai basil), oregano, thyme, parsley, rosemary, chives, and bay leaves all benefit from the consistent moisture.  Regular harvesting encourages bushier growth, so you can enjoy a steady supply of fresh herbs.

2. Fruiting Vegetables and Shallow-Rooted Options

Take advantage of the water efficiency of wicking beds for moisture-loving fruiting vegetables. Juicy tomatoes (cherry tomatoes, roma tomatoes), colorful capsicums (bell peppers), and prolific cucumbers (slicing cucumbers, Lebanese cucumbers) will thrive with support structures for vining varieties.

For shallow-rooted vegetables, wicking beds are ideal. Delicious zucchini (courgette), tasty eggplant (aubergine), and vibrant snow peas are excellent choices as their root systems don’t require excessive depth.

3. Strawberries

Indulge in the sweetness of homegrown strawberries. Their spreading growth habit is well-suited to the ample space of a wicking bed. Choose ever-bearing varieties for continuous harvests throughout the season.

FAQs

1. Are wicking beds suitable for all climates?

Wicking beds offer advantages in most climates, but there are a few things to consider. In hot and dry climates, wicking beds excel at conserving water and delivering consistent moisture to plants.

However, in places that get frosts with frequent freezing temperatures, the water reservoir can freeze, potentially damaging the bed and harming plant roots.

2. Can wicking beds be used indoors?

Wicking beds can potentially be used indoors, but with some adaptations. The key challenge is providing sufficient light for your plants to thrive.  While window light can work for some shade-loving plants, most vegetables and herbs require significant sunlight.  Supplementing with grow lights can be a solution.

Another consideration is the size and location of your indoor wicking bed.  Make sure it fits comfortably within your space and has proper drainage, especially if using a grow light setup.

3. How often do I need to refill the reservoir in a wicking bed?

refill frequency for your wicking bed reservoir depends on several factors:

• Climate: Hotter and drier climates will see faster water usage by plants, requiring more frequent refilling. Cooler climates with higher humidity might require less frequent filling.
• Plant type: Plants with higher water needs will naturally draw more water from the reservoir, leading to faster depletion. Drought-tolerant plants will require less frequent refills.

The best way to determine refill frequency is to monitor the water level in your reservoir.  Most wicking beds have a visual indicator like a sight glass or fill tube.  Aim to keep the reservoir at least half full for optimal plant health.

4. How do I choose the right plants for my wicking bed?

Choosing the perfect plants for your wicking bed involves considering a few key factors:

• Moisture needs: Wicking beds offer consistent moisture, so plants that thrive in well-drained but consistently moist soil are ideal. Leafy greens, herbs, and many fruiting vegetables like tomatoes and peppers excel in this environment.  Plants that prefer drier conditions might not do well in a wicking bed.
• Root depth: Shallow-rooted plants are generally better suited for wicking beds as they can easily access the moisture in the reservoir zone.  Deep-rooted vegetables like carrots might struggle due to limited space for root development.
• Sun requirements: Research the sun requirements of your chosen plants and ensure your wicking bed receives adequate sunlight throughout the day.  Some plants might need additional lighting adjustments depending on your location.
• Plant size: Consider the mature size of your chosen plants and choose varieties that won’t overcrowd the bed or restrict access to sunlight for other plants.