When to sow cosmos seeds? A detailed guide to growing methods

Cosmos plants are tall, with light and colorful flowers. They can be used as cut flowers or as urban landscape flowers. Sowing and propagation is the main method of propagating cosmos, so how do you plant cosmos seeds? Which months are suitable for planting?

1. How do you plant cosmos seeds?

1. Land preparation and bed preparation

Cosmos has a relatively shallow root system, so the depth of land preparation is generally kept at 20-30cm, and according to soil texture, sandy soil should be shallower while clay soil should be deeper. Before plowing, spread organic fertilizer and peat soil on the soil surface, and plow them into the lower soil together with the topsoil as a base fertilizer, while also improving the soil.

In fact, the process of land preparation can also play a certain role in killing insects, sterilizing, and weeding, and has a very good preventive effect against pests, diseases, and weeds.

2. Seed soaking treatment

Before sowing cosmos, soak the seeds first. Soaking can ensure that the seeds absorb enough water in a relatively short time. At present, there are two methods: soaking in cold water (25℃-30℃) and soaking in warm water (50℃-55℃).

By comparison, soaking in warm water is better than cold water and takes less time. When using warm water soaking, soak the seeds for 12 hours. During soaking, provide the seeds with suitable temperature and oxygen, maintain the relative humidity of the air, and promote seed germination. The soaking time should not be too long, as the seeds are prone to rotting.

3. Sow at the right time

Cosmos is relatively suitable for sowing in spring and summer. If sown in early spring, it can bloom in May-June; if sown in July-August, it can bloom in October.

Because cosmos seeds are relatively small, broadcast sowing and drill sowing can be combined. First dig ring trenches with a 20cm trench spacing. To prevent overly dense seedlings, mix fine sand and seeds at a 10:1 ratio, stir them together, and sow them together. After sowing the seeds, covering them with a layer of fine soil is enough.

After sowing is completed, in order to improve the germination rate, the soil can be properly sprayed with water. Of course, if there is a lot of rain, then some rain protection measures need to be taken, such as covering with a layer of film.

2. Which months are suitable for planting cosmos?

1. Planting time for cosmos

Planting here refers to thinning and setting out after cosmos sowing. Generally, the first thinning is carried out when the seedlings have all emerged, the cotyledons have fully unfolded, and true leaves begin to grow. The second thinning is carried out when there are 3-4 true leaves. If sown in early spring, thinning and setting out can usually be carried out around the end of March; if sown in summer, thinning and setting out is usually carried out at the end of August.

2. Management after cosmos planting

(1) Watering

In seasons with abundant rain, usually water only when the sun comes out and clears and the soil looks dry and pale; in dry seasons, water 1-2 times a week to keep the soil moist.

(2) Fertilizing

Apply organic fertilizer as a base fertilizer. Of course, chicken manure and peat soil can also be mixed into the soil as a base fertilizer. During the growth and development stage, multiple topdressings are needed.

(3) Light

Light also has a great influence on the growth and development of cosmos seedlings. Under conditions of sufficient light, the plants grow robustly and bloom more, so the site should be chosen in a sunny place.