When should cucumbers be fertilized, and what type of fertilizer works best?

Cucumber, also known as huqua or qinggua, belongs to the genus Cucumis in the family Cucurbitaceae and is one of the major greenhouse crops. Cucumbers have high water requirements and strong water‑absorbing capacity; therefore, they should be cultivated in soils with excellent water‑retention properties and require regular fertilization.

Fertilization Management for Greenhouse Cucumbers

1. Increase the application of organic fertilizers. Organic fertilizers not only supply cucumbers with a full range of nutrients for growth and development, but also reduce soil bulk density, increase soil porosity, and improve the soil’s physical and chemical properties. Therefore, organic fertilizers play a key role in maintaining high and stable yields while activating and improving the soil. In production, apply 2,500–3,000 kg of well‑decomposed farmyard manure per mu, or 120–400 kg of commercial organic fertilizer per mu. 2. Apply chemical fertilizers judiciously. Cucumber root systems are shallow and relatively delicate; overly concentrated applications can cause root burn. When using chemical fertilizers, adopt a strategy of frequent, small‑dose applications. For base dressing, apply 50–100 kg of a balanced, active humic‑acid compound fertilizer per mu. Throughout the growing period, supplemental topdressing should be applied as needed.

Key Points for Early Spring Greenhouse Cucumber Cultivation

1. Prepare the plot thoroughly: disinfect the greenhouse, cover it early, and heat the soil. Install the plastic mulch 20–30 days before transplanting; for older greenhouses, carry out thorough disinfection—spray the support posts and the plastic film with trisodium phosphate or sodium hypochlorite, or use fumigants such as chlorothalonil. After the ground thaws, promptly till the soil and apply sufficient base fertilizer, prioritizing organic fertilizers. Use raised beds and cover them with plastic mulch. 2. Transplant seedlings as early as possible, ensuring they are protected from frost damage; maintain a soil temperature of over 12°C at a depth of 10 cm inside the greenhouse, with nighttime temperatures no lower than 5°C. Plant at an appropriate density—about 4,000 plants per mu—and ensure shallow planting. 3. Greenhouse management—temperature control: For early spring cucumber cultivation, the primary focus in the initial stage is to maintain…