For years I’ve sown mustard as a green manure in autumn with the side benefit that it provides a few tender leaves for the kitchen before it’s killed by the cold. Only recently did I come round to the idea of growing mustard in spring, because everything you read about mustard says ‘Don’t grow it in spring’!
And for good reason. As days lengthen and warm up mustard, like many leafy greens, accelerates towards the culmination of its growth cycle: flowering and producing seeds (also known as bolting), which spells the end of tasty edible leaves. But there are two very sound motives for allowing mustard plants to bolt: to save seeds for replanting, or to make your own mustard.
Growing Mustard for Seeds
Growing mustard in spring is just as easy as growing it later in the year. Broadcast purchased or saved mustard seeds over the soil surface and lightly rake them in. You will get a lot of mustard seeds from just a few plants, so don’t devote too large an area to them unless you really, really love mustard! Water them after planting. A little dry weather while the plants are growing is not the end of the world – it may even hasten the plants to bolt a little sooner – but don’t let them dry out to the point of wilting.
You can pick a few leaves as required for eating, but be sure to leave plenty on the plants so they remain vigorous. Feeding isn’t usually necessary, but an occasional light application of diluted seaweed fertiliser will promote overall plant health.
Harvest mustard seeds when the pods dry to pale brown. Crunch the pods between your hands to release the seeds into a bowl or paper bag, then store them somewhere dry until you’re ready to use them. Black or brown seeds are typically stronger-flavoured than yellow ones.
How to Process Mustard Seeds
Making your own mustard sounds like it would be impossibly time-consuming and complicated, but it’s actually incredibly simple.
The basic ingredients for a jar of homemade mustard are mustard seeds and cold water. (I love recipes with short ingredients lists!) As a gardener with a tiny kitchen and puny cooking skills, keeping things simple is a must for me. And it must be worth my while: I don’t have the space, the time or the patience to grow and cook anything I don’t truly enjoy. You can’t beat a pungent, grainy mustard stirred into cheese sauce, poured over macaroni and topped with slices of tomato and grated cheddar, then grilled until singed and bubbling... mmm!
Mustard seeds need to be ground down into a powder to release their spice, which is why most recipe methods call for a pestle and mortar. I don’t own a pestle and mortar (who does?) so I opt for a less vigorous alternative. Soak seeds for a day or two in a jug of cold water. Once the seeds are swollen and softened, bung them into a food processor, together with the remaining liquid, and whizz up into a coarse mustard. You can strain through a fine sieve if you prefer a smoother texture.
Flavouring Your Homemade Mustard
Homemade mustard made from ground seeds and cold water will lose its kick after a few days, but include an acid such as lemon juice or cider vinegar and the acidulated mustard will remain spicy and keep seemingly forever in sterilised jars.
Adding salt brings out the flavour and helps to preserve the mustard further. Herbs and spices can be added to personalise your homemade condiment. Tarragon is often recommended, while honey is very popular for those of us with a sweet tooth. Some people add wine or beer to their homemade mustard, but personally I’ve always had a bit of a mental block about adding alcohol to cooking; it seems such a waste, especially when a good bottle of beer or wine isn’t cheap. And do I really want to ruin a recipe with bad alcohol? No thanks – I’ll stick to using a decent vinegar.
The flavour of homegrown mustard improves with time, so let it rest for a few days before using. Mustard can be kept at room temperature, but refrigerating it preserves the flavour for longer. When making your own mustard is so simple, it’s surprising more gardeners don’t try it!