What are cotyledons? | Gardening On

Parts of an avocado seed

Parts of an avocado seed.

Every time a seed germinates we can get a very interesting surprise when the first leaves appear since they will not have the shape they are supposed to have. These flakes are known by the name of cotyledons or embryonic leaves and they have a very important function.

In fact, without them neither the tallest tree nor the smallest grass could exist. Do you know what cotyledons are? Not? Don’t worry: after reading this article you will know .

What are cotyledons?

Seedling of Carica papayaCarica papaya seedling

Seedling of Carica papaya

From the first moment the embryo is formed inside the seed, the cotyledons also begin to mature. These first leaves will grow with the energy reserves stored in the seed, so once said seed stops being fed by the mother plant, will spend the energy of its cotyledons.

The life of these is very short: as soon as the seedling has its first true leaves they will begin to dry since they will have exhausted their reserves. In addition, from that moment the new plant will be able to make food by itself.

Depending on where the cotyledons develop, two types of plants differ: epigealwhich are those that have them off the ground, or hypogeawhich are those that have them underground. In both cases they fulfill the same function: to feed the seedling until it produces the first leaves.

However not all plants have the same number of cotyledons. The palms, grasses, Orchids and the bulbous ones only have a single cotyledon, which means that they are monocotilédoneas; on the other hand, the rest of the plants are dicotyledons (two cotyledons).

How to take care of the seedlings when they still have the cotyledons?

The beginning of the life of plants is complicated, since they are very vulnerable to pests and microorganisms that cause diseases, apart from inclement weather. That is why it is very important to be aware of them, and provide them with the following care:


Cotyledons are embryonic leavesCotyledons are embryonic leaves

Image – Flickr / Ruth Hartnup

There are plants that want to be in the sun from the first moment, but there are others that are semi-shady. Knowing the light nonsense that we are cultivating is one of the most necessary things to do before sowing them.. Sometimes it is the case that, for example, you plant a cactus in semi-shade and then you want to go out into the sun,… and when you do, it burns. Why?

Well, because in those cases you have to get used to the little plants little by little and gradually, always avoiding the midday sun.

Species that can be sown in the sun

There are many who want and need sun from day one, like these:

  • Succulents (cacti, and many succulents except Gasteria, Haworthia, and Sempervivum)
  • Plants such as olive trees, almond trees, wild olive trees, myrtles, lavender, etc.
  • Aromatic plants, such as parsley or rosemary
  • Many palm trees, such as those of the genus Phoenix, washingtonia or Chamaerops
  • Horticultural plants, such as tomatoes, peppers, cucumbers, watermelons, or melons

Semi-shadow species

Although there are few compared to the sun, it is convenient to know them:


The substrate of a seedbed must remain moist, but not flooded. Whenever possible, rainwater or lime-free will be used, although if they are plants of Mediterranean origin (olive trees, wild olive trees, almond trees, carob trees, etc.), if the water has some lime it will not harm them.


While they have the cotyledons, it is not advisable to fertilize themsince the plants feed on the reserves of said leaflets. But when you see that they begin to wither, you can start with the fertilizer for example with liquid guano (for sale here!), following the indications specified on the package to avoid problems.

Preventive treatments

With the sole purpose of getting the seedlings to grow well, it will be necessary to perform some preventive treatments:

Against pests

Insects generally love young shoots, and there is nothing more tender than a newly germinated seedling. A simple bite on the stem is enough for us to lose it, so do not hesitate for a moment to keep the seedlings well protectedfor example by sprinkling diatomaceous earth around it (for sale No products found.), or with mosquito netting (this is especially useful in hot, dry places, which are a favorite with locusts and grasshoppers).

Against diseases

Fungi can kill seedlings in no time. To avoid it, they should be treated with fungicides, or copper or sulfur sprinkled on the ground from time to time (every 15 days approximately) in spring. In this way, they will have a better chance of continuing to grow.


Seedbeds need special care

Seedbeds need special care

When should a seedling be transplanted? It depends a lot on the species and the conditions of the place where it is being grown, but in principle it will be transplanted when:

  • roots grow out of drainage holes,
  • has spent more than two years in the same pot,
  • be about two inches tall.

I hope it has been useful to you .

What are cotyledons? | Gardening On

Leave a Reply

Scroll to top
%d bloggers like this: