How To Grow Mustard Greens From Seed

Before moving to the South, the only mustard I’d ever heard of was the yellow stuff you squirt on your hotdog. I’d never heard of “mustard greens”, and I had no clue that the condiment by the same name actually came from the seeds of a plant!

This year I’ll be trying my hand at growing mustard greens for the first time. I’ve chosen “Southern Giant Curled” Mustard, an heirloom purchased from Baker Creek Seeds.

I don’t really like “greens”, as cooked here in the south, but I keep hoping I’ll acquire a taste. Steamed or sautéed mustard greens are super good for you, much like spinach and kale.

I’m also interested in growing mustard for its seeds. I use a lot of mustard seeds when pickling, and I also use ground mustard to make mayonnaise and salad dressing (not to mention making that yellow condiment we all know so well), so it would be really awesome if I could produce my own for organic seasoning!

Mustard is a cool weather crop, so it should be planted at the same time as other brassicas- in early spring (2-4 weeks before the last frost-free date), or in late summer (about 8 weeks before the first fall frost) for harvesting all winter.

The flavor of these nutritious leaves is actually improved by cold weather and light frosts.

You can direct sow these seeds straight into the garden, or start them indoors a few weeks before the outdoor planting time.

Here’s how I do it…

First, get your hands on some containers to start seeds in.  I’ve used yogurt cups with great success. I happened to have these trays this time around, so that’s what I’m working with.

Fill your containers with Seed Starting Mix. Make sure it specifically says Seed Starting and not just Potting Mix. Plain ol’ potting mix doesn’t have the nutrients seedlings need to thrive.

Once your containers are filled, soak them thoroughly. If you are on city water, you may need to use filtered water for your plants. There are very harsh chemicals in treated city water which will hinder the growth of your seedlings.

Here’s what mustard seeds look like:

They look exactly like broccoli and cabbage seeds because they all belong to the same family. They’re planted exactly the same way as well.

Plant the seeds about 1/4″ deep in your seed starting mix. I like to poke a little hole in the dirt, drop the seed in, then cover it back over. I recommend planting two seeds per container, just in case one of the seeds doesn’t germinate.

Some people do three at a time, but I’ve found that to be quite wasteful- you can only allow one plant per tray cell to grow, and if all three seedlings emerge, two would be wasted.

The soil must stay moist while the seeds germinate. You can either set your containers in a shallow tray with a little water in the bottom, or you can keep the soil moist by spritzing the trays with a spray bottle if they start to dry out.

Don’t forget to label your trays! Also, make a note of when you started your seeds so you can write in your garden journal how long it took them to germinate. Keep track of how many weeks old they are to best judge transplanting time.

I usually cover my filled trays with loose plastic bags, to create a mini greenhouse effect, and set them on top of the fridge to germinate in a warm place.

It took about six days for my seeds to germinate. As soon as any seedlings have emerged, they need to be put under a grow light or in a warm, south facing window if you have one.

Don’t worry about the seeds which are still germinating and haven’t showed themselves yet, they’ll pop up in another day or so.

We use a shop light with regular halogen bulbs as our grow light. The light needs to be about 1-2 in. from the tops of the plants. I usually turn the light on when I wake up in the morning, and turn it off around 8pm.

Here are my mustard seedlings 21 days after being planted. I’ve pinched off the first set of leaves so that all of the plant’s energy goes into growing the “true” leaves.

When the plants get a few sets of true leaves, it’ll be time to transplant them outdoors. But more on that when the time comes.

Do you grow mustard greens? Have any tips to share?