Onnu Biochar

Biochar Compost Mix for Seeds

£19.00 GBP

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A gentle blend of biochar and compost to give your seeds a perfect start in life. Easy to apply, you seeds will love the rich, fertile soil designed specifically for new, healthy growth.

Size 20L Bag 40L Bag Bulk Bag (1.7 m3)

Quantity

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✅ EBC-Certified Biochar ✅
📦 Free Shipping on all 20L & 40L bags 📦
🌿 Peat Free 🌿

Biochar (10%) and Compost (90%) blend

Our Biochar Compost Mix for Seeds is the perfect product for optimal seed germination and early plant development. This gentle blend of 10% biochar and 90% compost is thoughtfully curated to create an ideal environment for young seedlings, minimising the risk of nutrient burn and supporting healthy soil development over time.

The biochar component, produced through the pyrolysis of waste wood, enhances nutrient retention while creating an ideal habitat for beneficial microbes—perfect for nurturing young seedlings and plants. This sustainable, eco-friendly addition works harmoniously with premium compost, providing rich organic matter that gently decomposes to release essential nutrients for early root development. Together, these components create the perfect mix that enriches the soil with organic nutrients, supporting a balanced nutrient cycle. Nutrients are absorbed and gradually released to seedlings and plants, minimising nutrient leaching and fostering long-term soil health from the start.

Our biochar is EBC-certified, ensuring our products are safe, effective, and environmentally responsible. You can find out more about what EBC-certification means here.

Want a full rundown on biochar, how it is made, it's benefits and sustainability credentials? Click here to find out more.

Key Features

The biochar is mixed with premium compost made from coir, vermiculite and organic fertiliser.

Gentle Nutrient Release - Provides a slow and steady release of nutrients ideal for seedlings, reducing the risk of nutrient burn.

Enhanced Moisture Retention - The biochar's porous structure holds water efficiently, ensuring seeds and young plants have consistent moisture for healthy germination.

Optimal Aeration - Improves soil structure, allowing roots to access oxygen, which is essential for robust root development in early growth stages.

Microbial Habitat - Creates a favourable environment for beneficial soil microbes, supporting soil health and promoting nutrient availability for young plants.

Balanced pH -Helps moderate soil pH, making it suitable for a wide range of seeds and promoting balanced nutrient uptake.

Reduced Nutrient Leaching - Retains nutrients near the root zone, reducing nutrient loss and ensuring young plants have access to essential nutrients as they grow.

Sustainable and Eco-Friendly - Made from renewable materials, this blend is an environmentally conscious choice that supports soil health without the need for chemical fertilisers.

Application

Seed planting:

1. Prepare the Tray: Fill the tray with the Biochar Compost Mix for Seeds up to just below the rim, taking care not to compact it excessively. A gentle tap on a hard surface will settle the mix just right, creating an ideal base for your seeds.

2. Initial Watering: Water thoroughly and allow the tray to drain fully, ensuring the product is evenly moist but not saturated.

3. Seed Placement: Carefully place seeds on the surface of the mix, spacing them as needed. This ensures each seed has ample room to develop into a healthy seedling.

4. Cover with Mix: Add a layer of compost mix on top of the seeds, with a thickness matching the seed's size (e.g., cover a 1mm seed with 1mm of compost). This protective layer provides the seeds with the ideal conditions to sprout.

5. Water Gently: Use a fine rose watering can to moisten the tray lightly. Coir and biochar retain moisture well, so water sparingly. If needed, cover the tray with polythene or glass to maintain humidity. Always check moisture levels just below the surface before re-watering, even if the top layer appears dry.

6. Provide Indirect Light: Keep the tray in a location away from direct sunlight, as gentle, indirect light is perfect for nurturing germinating seeds without risking overheating or drying out.

Postage and Packaging

Shipping is free on all 20L & 40L bag purchases. Bulk bags are shipped on a pallet costing £49.99 each.

We expect to send out orders within 5 business days of receiving them, and they should arrive within 2-3 business days.

Please note: due to our evolving sustainable packaging strategy, product may not be shipped with the same bag design as shown.

Great for Tomato Seeds

I used this for germinating tomato seeds indoors and it worked fantastically, all the seeds developed to seedlings and I have even had fruits from some already too!

Thank you for taking the time to leave a review for our Biochar Compost Mix for Seeds, Ciaran. We're thrilled to hear that it worked so well for your tomato seeds! We designed this product specifically to help with germination and it's great to hear that it delivered great results for you.

Bulk enquiries

Looking for more than 5 bulk bags? For larger orders in bulk bags or delivered loose, and to benefit from our volume discounts, visit our commodities business, Onnu Bioflow, or email info@onnubioflow.com.

Onnu Bioflow

Want to trial biochar?

Running a trial? We can advise on how to set it up so you can measure the impact of the biochar. Contact us for more information!

Biochar

Factsheet

Our factsheet is a comprehensive guide for biochar and how it works. With summaries, glossaries, property tables, product descriptions and application rates, this fully-referenced factsheet can help you familiarise yourself with the world of biochar.

Download

Additional

Services

Biochar Implementation Plan

A tailored strategy to integrate biochar into your soil management and growing practices.

Learn More

Biochar Trial Support

Personalised consultations to address your unique soil challenges and goals.

Learn More

Biochar Bespoke Blends

We can make a bespoke product to match your precise requirements.

Learn More

Biochar Sieving

Whether you need fine biochar, or larger particles, our sieving service ensures consistency and quality in every bag you receive.

Learn More

Amazing product

Amazing product - I use it everywhere I can !

Thank you so much for your kind review! We're thrilled to hear that you're loving our Inoculated Biochar and using it all over your garden. Hope you enjoy the results!

Great stuff

Great stuff. I already bought a second big bag. Usually I charge the biochar for about 2 weeks with sprayed seaweed solution, rock dust, mycorrhiza fungi, seaweed meal and nettle/yarrow/plantain rotten "tea", then apply as top dressing to my beds. Biochar can also be used to make DIY water filter alongside sand and gravel. Powdered can be taken with water internally in case of poisoning.

Thank you for your kind review of our Pure Biochar. We're thrilled to hear that you find it to be great stuff and that you've already purchased a second bag.

We love your method of charging the biochar with various nutrients and using it as a top dressing for your beds. It's also great to hear that you're putting it to use in other ways. Enjoy!

Great service

Great service, great product.

Thank you for your positive review! We are thrilled to hear that you had a great experience with our service and that you are satisfied with our Pure Biochar product.

Delivered promptly

Delivered promptly. Product looked good. Spread on beds to counteract herbicide residue in compost so hoping and waiting to see results but looking good at this stage.

Thank you for taking the time to leave a review for our Inoculated Biochar. We are happy to hear that it was delivered promptly and that the product looked good. We hope it is effective in countering the herbicide residue in your compost and we look forward to hearing about your results!

Excellent value

Of course only time will tell but this certainly looks the part and seems good value.

Thank you for taking the time to leave us a review. We are thrilled to hear that you are satisfied with our Inoculated Biochar product and hope that you (and your garden) enjoy the long term results.

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Biochar Compost Mix for Seeds