So how much Nitrogen should you apply and when? As a qualified plant nutritionist, the answer to this is quite complex and depends on several things such as the previous crop grown, any organic manures applied and the concentration of Nitrogen in the fertiliser product you are going to use. A general guide is around a third in the planting bed, another third to a half 4-6 weeks later when the plants are established and the remainder in the autumn. As Nitrogen is very mobile in the soil and can easily be leached away by rainfall. Splitting the Nitrogen dressing in this way helps keep losses to a minimum and ensures nutrients are available when the plants demand is greatest.

For me the two post planting dressings of Nitrogen are by far and away the most important. When Brussels Sprouts have rooted growth is fast and you need to encourage tall stems, as tall stems equals lots of sprouts!

My fertiliser of choice is Pro Grower Veg and Brassica. This Product has 15.5% Nitrogen in a quick release formulation to give the crops an immediate boost when needed. 18% Calcium to ensures proper cell wall formation and strong stems. Boron, included as a trace element, is essential to help prevent hollow stems and brown internal markings in brassicas, which can lead to lots of issues with rotting. The first dressing is evenly applied at around 65 gsm. This coincides with the main growth phase of the plants. The second at around 50 gsm in early to mid-autumn helps ensure good sprout formation and as the plant grows throughout the wintertime, continued cropping.

For an organic alternative I would use Dried Blood (12% N) at 80 gsm for the first application and 66 gsm for the second, although over time, use of this product will acidify your soil. Brussels Sprouts can be quite challenging to grow successfully, but with good nutrition and a net to stop pigeons eating them in the winter months there is nothing quite like the taste of freshly picked sprouts for the festive dinner plate.