Moldy sprouts or mould on sprouts are usually just thin roots. Learn how to recognize them, so you feel good even with your fluffy plant friends.


Do you recognize this scenery: You have done everything right with the soaking in cool clean water and you have poured the seeds into a clean sprouter. The sprouter is placed in shade in your clean kitchen. You have rinsed twice daily, but still on day three the sprouts form mould. Again and again.

What is going on?!

Not to worry. The mould on your sprouts is probably just very fine roots called root hairs. They are natural and in this article, I will teach you about them.

Mouldy broccoli sprouts is root hairs
mouldy radish sprouts versus root hairs


You can know root hair by 5 characteristics:

  • Root hair is formed from 2-3 days. They are always thin, fine and white.
  • Root hair grows thicker as the sprout grows.
  • Your sprouts smell like a healthy plant when it is root hairs. They do not smell like wet soil.
  • Root hairs are only formed on the root itself. They are never formed on stem or leaves.
  • Root hair sticks to the root, and break easily.

So study your sprouts closely to recognize root hairs from mouldy sprouts.


Mouldy sprouts or better said sprouts with root hairs is a specific group of plants that form these fine, dense roots that resemble mold. The sprout varieties that form these are:

Broccoli · Radise · Pink kale · Rape · Cabbage · Mustard · Sunflower · Grain (Barley, Wheat etc.)

All other varieties of your sprouts in stead form long, slender single roots. Those are roots without root hair. Sprouts with single roots are:

Fenugreek · Endive · Fennel · Lentil · Alfalfa · Clover · Mizuna · Mung bean · Rucola · Pea

Mouldy sprout roots or single roots


Whether your sprouts form roots with or without root hairs has little to do with your cultivation of the plants. The root type is a part of the plants DNA and is all about pure survival for the plant.

Darwin and later scientists found that any species on this planet looks like it does because it is useful for the survival of that specific species. Only the strongest and best-fit plant survives to the stage where they form the next generation. So root hairs or not is quite simply basedon the plant’s strategy for survival.

The interesting thing is that plant roots do not grow randomly. They are always looking for moisture and nutrients the plant needs to form its leaf parts and to stay healthy. Plants with root hairs have the advantage that the roots can sift the soil close to the plant for moisture and nourishment and absorb everything. The disadvantage is that the plant is vulnerable to local drought due to its compact and often short roots.


As roots with root hairs is one strategy for a plant, roots without root hair – single roots – is simply another strategy. Both aim to ensure the best possible survival of the plant.

Plants that form single roots have the advantage that they can grow long, deep and fast. Only when the roots have reached a certain depth or encountered certain nutrients, the roots will develop side roots.

Single roots are therefore as smart a strategy as root hair. It’s just another strategy. You cannot control the type of roots on your sprouts – that choice was made by Mother Nature long before the seed landed in your kitchen.

The beauty of growing your own sprouts is that the small plants get all the necessary nourishment from the seed itself. You only need to rinse the sprouts twice a day for them to get enough moisture and – voila – you have a nutritious, crisp sprout for your food.


You cannot influence if your sprouts form root hairs or not. It is the plant’s DNA that determines this.

On the other hand, you will notice that if you forget to rinse your sprouts morning and evening or it is very hot in your kitchen, then your sprouts will form longer roots ant thus also more root hair.

This reaction to the lack of moisture lies in the plant’s genes, as the purpose of root hair is precisely to absorb all the moisture that is around the roots.

Less moisture = more dense roots.

If the plant therefore feels that it is dry, it reacts by “taking the chance” and forming even more root hairs.

A chance?

Yes, because growing roots is a chance, as it requires energy and nourishment of the seed to develop more roots.

Therefore, if you want maximally nutritious sprouts that have not ‘wasted’ energy on forming to much roots, you should rinse regularly and never stress the plants with a lack of moisture.

Sprouts with root hairs in food


Roots are full of fiber and some nourishment too. Luckily you can eat your whole sprout regardless of whether they have a single root or the wild root hairs.

All roots typically have very little flavor. This makes it easy to use all roots in smoothies or blended into dips, if you do not find it optimal to use them whole in your salads, as topping etc.

The only important trick when you eat the roots is to rinse them clean as you do with the rest of the sprouts.


If you wish extra clean sprouts for your food, here is an extra tip: Just before you eat the mature and harvested sprouts, you can soak them in cold water mixed with 1/10 fresh organic lemon juice.

Let the sprouts sit in this mixture for 10 minutes just before you use the sprouts in your dishes. The lemon will neutralize any bacteria that may reside between the dense roots.

Rinse away the lemon  juice after the 10 minutes and your sprouts are completely clean. But note that you cannot save the sprouts after this treatment as the lemon is harsh both on bacteria and on the plant tissue on your fragile sprouts.

Mouldy sprouts cleaned with lemon


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