# A smart biological strategy for growing onions and other allium crops in NZ using Rootella F - Link: https://rd2.co.nz/biological-strategy-growing-onions-nz-rootellaf/ - Published: 2025-06-10T23:51:21+00:00 - Author: RSF Admin Growing allium crops, such as onions (the second-largest export crop in Aotearoa, New Zealand), is an essential part of our horticultural production. With ongoing pressure from markets to reduce synthetic inputs and improve crop performance, many commercial growers are turning to biological tools to optimise their systems. If you’re growing onions  one of the most effective ways to support strong early establishment is by inoculating onion seeds with Rootella F before planting. This mycorrhizal-based approach is gaining traction across allium-producing regions. It offers improved nutrient access, better root development, and more consistent results, even in variable soils. Allium crops are known to suffer in the absence of mycorrhizae! ### Why soil biology matters in onion production Whether you’re growing on heavy clay, sandy loams or anything in between, allium crops, particularly onions, are sensitive to nutrient lock-up, early-season stress and are shallow rooting. Onions have a notoriously difficult time taking up nutrients due to their shallow roots. Strong root development is therefore crucial when growing onion seeds, particularly in large-scale field production, where uniformity and stand establishment significantly impact final yields. Rootella F is a concentrated endomycorrhizal fungi inoculant. The addition of mycorrhizal fungi (Rootella) during seeding of a new crop will increase strike rate and mycorrhizae act as a physical barrier to detrimental pathogens reducing plant loss.   Mycorrhizal fungi form a network of thin fungal strands that attach to roots and increase their effective range. This increases a crop’s ability to uptake nutrients and contributes to soil stability.  Extended root systems means improved uptake of minerals like phosphorus and nitrogen. This can effectively reduce fertiliser inputs of these often overused macronutrients, in turn reducing costs for growers. ### Inoculating onion seeds with Rootella F Applying Rootella directly to onion seeds before planting is an efficient and scalable method for enhancing early root colonisation. This technique introduces the fungi at the earliest stage of development, ensuring the mycorrhizal inoculation begins as soon as roots emerge. Rootella may be mixed with seed via planter box or applied in furrow to row crops dry, drip or spray application and at a rate of 120 grams/Ha via the planter box, this is a true economical and environmental choice.  It is important to plant the treated seed shortly after application to maximise the biological benefit. Enquire about our professional seed coating [Rootella X.](http://d2.co.nz/product/mycorrhizal-fungi-rootella-x-fine-powder-250g-organic-copy/) ### ⏎ Key benefits of using Rootella F on onion seeds Onion growers who incorporate Rootella into their production programmes see improvements in several areas: * **Enhanced nutrient uptake**: Especially phosphorus and nitrogen, phosphorus can become quickly complexed in the soil and tied up rendered non plant available under various weather conditions but Mycorrhizae bypasses this problem. * **Faster, more uniform emergence**: Leading to more consistent crop stands and better canopy closure. * **Improved water-use efficiency**: Mycorrhizal networks increase the plant’s ability to access water and minerals beyond the immediate root zone. * **Increased resilience**: Healthier root systems are better able to tolerate both abiotic stress such as drought, and biotic stress from soil borne pathogens. * Mycorrhizal fungi adds to your companies’ sustainability strategy, facilitating carbon storage and helping plants to cope with environmental stress such as drought and heavy metals These benefits are particularly useful in fields with a history of uneven emergence, high nutrient variability or low phosphorus and declining organic matter; Rewards come from both production and sustainability efforts.  ### **Best practice for growing onions in NZ with Rootella** **Avoid incompatible inputs**: Fungicide seed treatments or drenches may suppress mycorrhizal activity. Where possible, use compatible biologicals or apply fungicides away from inoculation timing. Check Rootella’s compatibility with various products [here.](https://rd2.co.nz/commercial/rootella-compatibility-tool/) A biological strategy that begins with growing onion seeds treated with Rootella F offers long-term advantages for commercial growers. By inoculating the seeds at planting, you give your crop the best possible start, enhancing root development, improving fertiliser efficiency and supporting stronger performance across variable soil conditions.  It’s a practical, cost-effective approach to achieving higher yields and greater crop resilience in your allium blocks. ### Frequently asked questions **Can I apply Rootella F directly to onion seeds?** Yes. Onion seeds can be inoculated before or during planting which ensures early inoculation as roots develop. **Is Rootella F suitable for all commercial onion varieties?** Yes. Rootella is beneficial for all onion cultivars and allium crops grown in New Zealand and works effectively across a range of soil conditions. **Does Rootella work in conventional and organic systems?** Absolutely. Rootella F is certified organic and compatible with both organic and conventional production systems. **How does Rootella support crop performance in challenging soil conditions?** Rootella helps plants establish stronger root systems, which is especially beneficial in soils with low phosphorus availability or in cold climates. By improving nutrient uptake and access to moisture, Rootella supports more uniform growth and better resilience across variable field conditions. * ![Rootella X](https://rd2.co.nz/wp-content/uploads/2022/02/Rootella-X-mycorrhizal- fungi-300x300.jpg "A smart biological strategy for growing onions and other allium crops in NZ using Rootella F 1") * Rootella X-Mycorrhizal Fungi (New Zealand Native) Commercial Seed Coating-250g- Organic * $1,485.94 * [Add to cart](https://rd2.co.nz/biological-strategy-growing-onions-nz-rootellaf/?output_format=markdown&add-to-cart=9332) * ![Rootella-P-1kg pouch Mycorrhizal Fungi](https://rd2.co.nz/wp-content/uploads/ 2022/02/Rootella-P-1kg-pouch-Mycorrhizal-Fungi-300x300.jpg "A smart biological strategy for growing onions and other allium crops in NZ using Rootella F 2") * Rootella P – Mycorrhizal Fungi (New Zealand Native) – Organic * $129.48 * Rated **4.80** out of 5 based on 5 customer ratings * [Add to cart](https://rd2.co.nz/biological-strategy-growing-onions-nz-rootellaf/?output_format=markdown&add-to-cart=96268) * ![Mycorrhizal fungi Rootella G](https://rd2.co.nz/wp-content/uploads/2022/02/ Rootella-G-1kg-pouch-Mycorrhizal-Fungi-300x300.jpg "A smart biological strategy for growing onions and other allium crops in NZ using Rootella F 3") * Rootella G – Mycorrhizal Fungi (New Zealand Native) – Organic * $129.48 * Rated **4.75** out of 5 based on 8 customer ratings * [Add to cart](https://rd2.co.nz/biological-strategy-growing-onions-nz-rootellaf/?output_format=markdown&add-to-cart=96816)