Article by David Marks
There are two key reasons for growing mustard in the UK, the main one being to use it as a green manure on soil. This article however is concerned with growing mustard plants to use as a spice. To be honest up front, there is no commercial reason for the average gardener to grow the plants and making their own mustard, the economics, time, effort and timescales just don’t add up.

However, some of you, me included, may just want to give it a try for the novelty value and the satisfaction of knowing you’ve made it yourself. One thing you can be sure of, tell friends and family that you have made your own mustard and they will all want a little jar!

Having grown and made your own mustard, you may just end up wanting to experiment with different types of seeds. In general, the darker the seed the stronger the flavour. All sorts of things can be added to mustard to enhance the flavour; beer, port, spirits, honey and herbs are just a few ideas. See the end of this article for suggestions and recipes.

On a practical note, the hardest part of the process will be obtaining the little jars to store the stuff in! Those jars don’t grow on trees so start saving them up now before you begin planting.


Mustard will grow in just about any soil without any problems. It prefers a neutral soil but slightly acidic or alkaline soil is unlikely to give it problems. Avoid waterlogged soils and if your soil is sandy add lots of well rotted organic matter.

Although it’s a cool weather crop (great for the UK in spring and early summer) it does prefer a full sun or light partial shade position. Expect the plants to grow to about 60cm high.

One key point with mustard plants is to remember that they are from the same family as broccoli, cabbage, cauliflower etc. so they should be treated as such in any crop rotation plan.


Mustard seeds are one of the easiest crops to grow. Quite literally you could throw some on a bare patch of land, water them and end up with a good crop. Probably a better idea is to dig the soil first, draw a 1cm groove in it with a trowel and lightly sprinkle seeds in the groove. Cover the seeds with earth and water well. If you are growing more than one row space the rows 30cm / 10in apart. It’s best, but not absolutely necessary, to thin the seedlings to 30cm / 10in apart.

The best time to sow the seeds is a couple of weeks before the last frost date so sow mustard seeds around mid April. The seedlings should appear in a week to ten days and grow rapidly.


On any reasonable soil the only care mustard plants require is watering in dry conditions. Don’t bother feeding them unless your ground is poor quality. Because the foliage is so dense, weeding will almost certainly not be required. The plants are more than strong enough to kill almost everything else!

Your mustard plants will grow quickly and reach about 60cm tall in 6 weeks or so when the yellow (sometimes white) flowers appear and the pods begin to form.

You will encounter one possible problem with mustard plants, slugs and snails. The damp and dense foliage will become a favourite hiding place for them. They won’t attack the mustard plants but will come out of their hiding place at night to attack nearby plants so be aware of that.


Mustard grows well in large containers full of multi-purpose. Water frequently to keep the soil moist and feed with a general purpose liquid fertiliser once a fortnight.


The key rule about harvesting is to do it before the seeds are fully ripe. The reason for thisis simple, if you let the seeds fully ripen they will spread of their own accord all over your garden and self-set. As the seed ripens the pods will turn from green to light brown and they should be harvested at this stage.

Store the pods in a warmish place (inside a house is fine) which is also dry. The pods will ripen after two weeks or so. Now the time-consuming phase: lightly squash the pods and the seeds will be released. It’s these seeds which should separated from the pod casing and debris to be used to make mustard.

Mustard seeds will keep their potency for up to one year if stored in a tightly sealed jar in a cool dark place.


If you go online and look at seeds for sale by the major seed merchants you will are unlikely to find any being sold specifically for use to grow mustard plants for seeds. You have three sources which are:

  • Go to a local Asian deli who will sell a selection of seeds for cooking. Select one or two types remembering yellow seeds are mild, darker seeds, from brown to black, are progressively hotter.
  • Buy the seeds from Amazon.
  • Buy a small pot of mustard seeds from your supermarket (in the herbs section). This should be more than enough for a very decent crop of mustard.


There are many ways to make a decent basic mustard, we outline below a simple recipe which makes about 750g of excellent mild French mustard, enough for four small jars.


100g White mustard seeds

400ml Water at room temperature

200ml White winevinegar or cider vinegar

½ teaspoon of Salt

½ teaspoon of Sugar

Pinch of crushed Chilli flakes


Sterilise the jars and their lids. To do this wash them well in hot water. Place the jars and lids in a pre-heated oven upside down on a baking tray at 160°C / 325°F / Gas 3 for 15 minutes.


  1. Grind the mustard seeds using a pestle and mortar or use a food processor. The aim is to break up the seeds rather than grind them to a powder.
  2. Place the seeds in a glass container and add the water. Cover and place in the fridge for four hours or overnight.
  3. Pour off (but keep for later use) about a third of the liquid.
  4. Add the mustard mix, vinegar, salt and sugar to a food processor and blend for a minute or two.
  5. The mixture will probably be too thick so turn the food processor on again and slowly pour in a little of the saved liquid (step3) at a time until the texture is as required.
  6. Spoon the mustard into the jars and tightly place the caps on. The mustard will mature in the jars for a month or so, after that it will gradually loose its taste. Plan on using within three months if kept in the fridge.


The above recipe provides an excellent basic French mustard but you
may well wish to add some additional / different ingredients to make different types of mustard. The more commonly available types are listed below and these should provide you with than enough information to experiment.


Hotter than French mustard this type is made using a blend of white and brown mustard seeds to add some punch to the flavour. Vinegar is not used but to stabilise the mixture they use a different form of acid. Colman’s also sell a mustard in powder form and although this is probably better than the stuff in jars it is, of
course, not quite so convenient.


Hotter than conventional French mustard Dijon mustard replaces vinegar with the juice from unripe grapes. It also uses more salt than most other types.


This is any mustard where the seeds have not been fully ground down. This adds texture and a full bodied flavour. Traditionally it is made in a similar fashion to Dijon mustard.


The mildest of all the mustards, it is mixed with turmeric to give it the characteristic bright yellow colour.


Made with much less vinegar but with beer to add the liquid. A strong tasting beer is required if its falvour is to be appreciated.


Normally known as Chinese mustard this is normally the hottest of all. The seeds are brown and / or black which are the reason for the strength of flavour.