Why are coriander seedlings uneven? (Why are coriander seedlings so thin after they emerge?)

Coriander, also known as cilantro, is divided into large-leaf varieties and small-leaf varieties. The large-leaf variety has a higher yield, but its adaptability and fragrance are not as good as the small-leaf variety. The small-leaf coriander has a strong fragrance, is cold-resistant, and has strong adaptability, but has a lower yield.

Small-leaf coriander is more commonly grown in small family vegetable gardens, while large-leaf coriander is more commonly grown in large-scale cultivation because of its high yield.

Coriander is mainly cultivated in the open field in spring and autumn. In winter, it can be cultivated over the winter under protected facilities. In summer, due to the high temperature and heavy rain, it is rarely cultivated, but it is not impossible to cultivate it. It is just that sun protection measures such as sunshade nets must be set up.

When sowing coriander, there are often uneven germination. There are two reasons for this. First, the germination time is inconsistent, some germinations are early and some are late, with a difference of many days . Second, the germination is uneven, with more germinations in some places and fewer or even no germinations in other places .

The uneven emergence of vegetable seedlings is a very troublesome thing, which brings great inconvenience in management. You decide whether to manage the tall ones or the short ones, the dense ones or the sparse ones.

There are two different reasons for the uneven emergence of coriander seedlings, namely, inconsistent emergence time and uneven density, which need to be treated differently.

First, we must first understand the reasons for the uneven emergence of coriander seedlings:

1. Reasons for different germination times

(1) Seed problem

The germination rate of coriander seeds is very low in the first year, and it has to go through a dormant period of 5-6 months. The germination rate can be as high as over 90% in the second year, so we have to choose second-year seeds that are bright yellow, full in color, and have a strong aroma.

Coriander is a cold-resistant vegetable that prefers a cool environment. Its seeds have the characteristics of thermal dormancy. Without low-temperature treatment to break the thermal dormancy of the seeds, it cannot germinate well.

Before processing coriander seeds, you have to rub the seeds open first. Because they have a thick skin, you have to soak the seeds and germinate them at low temperature before sowing.

(2) The soil in the seedbed is unevenly dry and wet

Generally speaking, when we sow coriander, we must first water the bottom of the plant and wait for the water to seep in before sowing the seeds. If the bottom water is not evenly applied, the wet areas will generally sprout first, while the dry areas will sprout later.

(3) Uneven thickness of soil cover

After sowing, a layer of soil should be covered. It is appropriate to cover the coriander with about 1 cm of fine soil. Too thin soil will dry easily, and too thick soil will cause difficulty in unearthing. Uneven thickness will cause the seedlings to emerge early or late.

(4) The seedbed is uneven

When preparing the seedbed, you need to rake it flat. After watering, you can fill the low places with fine soil. Otherwise, the soil will be uniform, the low places will be thick, and it will be slow to emerge from the soil.

2. Reasons for uneven emergence of seedlings

The main reason for this situation is that you spread the seeds unevenly, or water them unevenly after sowing, or the third is the damage caused by underground pests.

Second, find a solution

First of all, the coriander seeds you choose should not be old seeds. That is to say, it is best to use seeds from the second year rather than seeds from the first year or three years later, otherwise all the methods below will be ineffective.

1. Spring sowing

Coriander is sown in spring because the temperature is lower and the seed coat is thick, so it is not easy to absorb water, which affects germination.

First, rub the seeds open and soak them in clean water for about 12 hours. After taking them out, control the moisture so that the seed coat is half dry and not wet. Then wrap them with a wet cloth and put them in a shady place to germinate to prevent the sprouts from drying out.

When germinating, stir the seeds once a day, and then water them again after 3-4 days. In about 10 days, more than half of the buds will appear, and you can then sow them.

If you don't soak the seeds to germinate, you can also dig shallow furrows and water them thoroughly before sowing. The thickness of the soil is about 1 cm.

2. Autumn sowing

Coriander seeds almost never germinate when the temperature exceeds 30°C. Therefore, when sowing coriander in high temperature seasons, dormancy must be broken by low temperatures in order to achieve a better germination rate.

Rub the seeds and soak them in clean water, wrap them with wet cloth, and put them in a plastic bag. They can be placed in the refrigerator for germination, or they can be placed in a well. Generally, the germination rate will be significantly improved in about 4 days.

Since coriander seeds are too small, it is not easy to sow or push the soil, so we can mix the seeds with fine sand and then sow them. The thickness of the soil should be 1-2 cm, otherwise it will lead to uneven emergence from the soil .

Especially in summer, when sowing coriander, due to the high temperature and scorching sun, rain erosion, and frequent water loss, the erosion is severe, which seriously affects the uniform emergence of coriander. Therefore, it is necessary to cover the sunshade net to prevent the impact of heavy rain, provide shade and cool down, and increase the emergence rate to ensure uniform emergence.