Using Coconut Coir to Maximize Growth in Raised Beds
How to Use Coconut Coir for Your Raised Beds
Coco coir, a derivative of coconut husk processing, is used to make brooms, animal bedding, rooting mats, hanging grow baskets, doormats, and thick ropes. It also offers many unique agricultural benefits. If you’re looking for an eco-friendly way to maximize healthy soil and grow big in raised beds, coco coir may be the amendment you’ve been looking for.
Growers can mix coco coir into their existing soil of raised beds or garden beds to assist with soil structure, compaction issues, maintaining nutrients, and improving drainage for better crop health. It’s pH neutral, inert by nature, light to ship, and reusable up to three times, making it an eco-friendly soil additive. While there are benefits and pitfalls, incorporating coco coir into your farm business and backyard homestead operation is easy.
Understanding Coconut Coir
Coconut coir, or coco coir, is a naturally antifungal and pH-neutral alternative to peat moss made from previously unused coconut waste products. Producers use the husk material surrounding the nut and flesh of the coconut (Cocos nucifera) to produce various coco coir substrates.
The farming community embraced this product for its remarkable water retention, ability to improve drainage, and environmental sustainability. The dense coconut coir bricks are easy to rehydrate and mix into existing soils, they can also be used in hydroponic growing as a substrate. When incorporated correctly, coco coir provides a perfectly stable and nutritious environment for seedlings' early growth and maturity stages.
Three different coconut products come from coconuts for use in traditional growing systems, raised beds, or hydroponically:
Coconut pith, peat, or coco dust has a thin, granular consistency when dry. When you add water, it plumps up and has a solid ability to hold onto moisture. Avoid using coco peat alone, as your plants’ roots may drown from all the moisture they hold onto. Its water retention abilities make it perfect in a mix for indoor seed-starting in cell trays or 1020 trays, especially those tiny seeds that require consistent moisture.
Coco fibers are often used to mulch around crops, trees, and houseplants because they're long and durable. When mixed with other growing media, they provide air pockets, but note that since they break down quickly, the air pockets will also diminish with time.
Coco chips combine peat and fibers, which creates a consistency and look similar to woodchips used as mulch, pathways, and landscaping.
When you combine these three by-products, you get coconut coir.
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Benefits of Coconut Coir
- Balances water and drainage - holds up to ten times its weight in water while preventing waterlogged soil, with a naturally balanced pH of 5.2 to 6.8
- Protects roots naturally - anti-fungal properties and pest deterrence keep roots healthy while improved aeration prevents root rot
- Easy to handle - lightweight, rot-resistant material with a soil-like feel that's simple for growers to manage and adjust
- Supports early growth - contains potassium and phosphorus ideal for seedlings and microgreens
- Sustainable choice - eco-friendly alternative to endangered peat moss from diminishing bogs
Coconut processors used to burn the by-products, adding to our atmosphere's carbon, but choosing coco coir helps offset these harmful effects while growers reap the benefits.
In an exciting study, Coconut Waste: Discovering Sustainable Approaches to Advance a Circular Economy (Vieira et al., 2024), researchers pinpoint new ways to repurpose coconut waste to promote responsible consumption and clean energy sources.
Disadvantages of Coconut Coir
- Growers must amend the coir before using it because of its low NPK levels. Mixes are available, but they are cost-prohibitive for some.
- It may contain high salt levels if not rinsed and processed correctly. Trustworthy distributors will rinse it in fresh water to remove excess salts.
- Growers may find it tedious to soak to rehydrate and break apart.
- Some producers mass-produce it and pile it up, leaving it vulnerable to pathogens.
To avoid chemically treated products, find a producer that is transparent with their processing systems.
Preparing Coconut Coir for Raised Beds
Coconut coir is condensed into tightly packed bricks before selling. It’s lightweight when shipped and easy to store. To rehydrate bricks:
- Place the coir brick into a plastic tub or bucket.
- Measure warm water according to the grams of water-to-coir ratio listed on the packaging.
If your packaging doesn’t contain this information, you can either (1) weigh your water and record how much worked for you so you’ll have it the next time you need it or (2) slowly add warm water until you like the consistency of the substrate.
The reabsorption process could take up to an hour depending on the brick size. When it's ready, the consistency should be soft and fluffy.
Don't need a full brick at once? You can slowly add water, scraping off what you need, then remove the brick and store it in a vented container to reduce the risk of mold.
Pro tip: Warm water is not required but will allow the coir to expand more quickly.
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Mixing Coco Coir
When mixing coco coir into existing raised bed soil, use a 1:1 ratio, adding horticultural sand, compost, or perlite to adjust the soil consistency. Test the soil first to avoid over-applying nutrients that can damage plant growth.
Sample Coco Coir Mixes You Can Try
| Mix Recipe | Ratio | Best For |
|---|---|---|
| Basic Coir-Perlite | 3 parts coir : 1 part perlite | Simple with good balance so roots don't drown |
| Seed Starting Boost | 4 parts coir : 1 part perlite : 1 part worm castings | Starting seeds with extra nutrients |
| Complete Growing Mix | 4 parts soil : 3 parts compost : 2 parts coir : 1 part worm castings | General growing and planting |
| Square Foot Garden | 1 part coir : 1 part vermiculite : 1 part compost | Replacing peat moss in Mel's Mix |
You can also add fish fertilizer or bat guano additives to your coco coir to make a nourishing grow media.
Many tried-and-true blends are available online and in gardening books, but the best one is the one that works for you in your setup.
Related: 1020 Trays & Flats
Planting in Coconut Coir-Amended Raised Beds
Once coconut coir is fully incorporated into your raised bed mix, it won't feel any different. However, you will need to trial some new watering practices.
Choosing the Right Plants
Coco coir affects soil pH, nutrients, and salt levels, so growers should choose crops wisely when starting. Select plants based on their nutrient requirements and moisture needs. Here are a few crop families that do well in coconut coir-amended garden beds.
| Category | Plants | Special Notes |
|---|---|---|
| Vegetables | Cherry & Roma tomatoes, Peppers, Eggplants, Cucumbers | Peppers require high soil nutrients |
| Fruits | Strawberries, Melons, Blueberries | Mix strawberries with perlite; use bush/dwarf blueberry cultivars |
| Herbs | Basil, Cilantro, Mint | Ensure basil beds are well-draining |
| Ornamentals | Geraniums, Orchids, Roses, Petunias, Begonias | Use 1:1 coir to potting mix ratio for orchids |
Raised beds amended with coconut coir products will allow many different plants to perform well. Experimenting and adjusting ratios of compost, perlite, native soil, and coco coir while keeping detailed data records will help your specific garden thrive.
Pro tip: Put houseplant cuttings like pothos, snake plants, and philodendrons in coco coir; the moisture retention capabilities and increased aeration help fool-proof watering schedules for beginners.
Related: 10 Must-Have Indoor House Plants for Gardeners and Plant Lovers
Ongoing Care
Coconut coir naturally contains high levels of potassium and phosphorus but lacks calcium and magnesium, which growers should closely monitor before transplanting crops to the raised beds. You will need to supplement with CalMag fertilizers to maintain balance in the flowering and fruiting phase.
All-purpose and slow-release fertilizers are not ideal when using coconut coir because they could result in over-fertilization and burned plants.
Soil test after each round of crops or biannually, especially if you are reusing coco coir, to ensure your raised beds continue to provide the nutrients plants require.
Pairing one of our DIY Portable Low Tunnel Kits with your raised beds is perfect for maintaining moisture during the shoulder seasons when you have greenhouse plastic on your tunnel.
Growers should adjust their watering schedules and techniques when using coco coir. Drip irrigation will work best and use a moisture meter for quick, easy readings if you're unsure.
Maintenance and Troubleshooting
The easiest way to check moisture is with a finger test. Place your first two fingers several inches down in the soil, and then pull them out. When there is soil on your fingers, the moisture levels are sufficient, but if they’re dry, it’s time to water.
Related: The Best Drip Irrigation for Container Gardening in Small-Scale Gardens
Pests are attracted to decaying matter, and since coco coir is slow to break down, few pests flock to it. Mulch coco fibers help dry soil surfaces, reducing algae growth and deterring pesky fungus gnats and fruit flies.
Since pest pressure is always possible in agricultural settings, scout and monitor as usual. If pests become a concern, rinse the coir with boiling water before reusing, add a higher level of perlite or fibers, or use sticky traps.
FAQs
How do I prepare coconut coir blocks for use in raised beds?
Rehydrate your coco coir brick by adding warm water to the coco coir brick in a watertight bucket. If you only need to rehydrate a portion of the brick, slowly pour warm water onto it, scraping away as it softens and expands, leaving the rest solid.
Can coconut coir be reused, and if so, how?
Growers can reuse coir up to three times before it’s no longer stable enough to use as a stable growing environment. To reuse, remove all of the plant roots and debris, soak in water for 24-48 hours to remove salts. Check the pH before adding to a new potting mix so you can adjust appropriately.
What vegetables thrive best in coconut coir-enhanced soil?
Many vegetables thrive from the drainage, aeration, water retention, and neutral properties coco coir offers. Bok choi, onions, leafy greens, cauliflower, peppers, and herbs are a few crops that will perform well in coir. Houseplants and ornamentals will also thrive in the right conditions.
How does coconut coir compare to peat moss regarding performance and sustainability?
Unlike the peat bogs from which we harvest peat moss, coconut coir is renewable and environmentally friendly. Covering less than 3% of Earth's land, peat bogs contain the largest store of natural carbon and help improve water quality, so we should do everything we can to keep them intact.
Using coconut coir and fibers creates a no-waste product. Since coconut coir retains moisture better than peat, growers can conserve water. When coconut coir has served its purpose, it is fully compostable. Unscathed peat bogs are a finite phenomenon that is quickly diminishing, so adjusting to this alternative and reusable product benefits everyone.
Are there any plants that should not be grown in coconut coir?
High salt levels can adversely affect crops, so growers should avoid growing those sensitive to salt levels. When growing cucumbers, celery, beans, and radishes, ensure you choose a product properly rinsed of tidal water salts.
Does coco coir change the pH of the soil?
Coco coir is pH-neutral, and since most vegetables require a balanced pH between 5.0 and 7.0, it is an excellent addition to your growing medium. Consistently using it can help balance acidic or alkaline soil levels.