TheNaturePlanet

What should you do if the leaves of your planted watermelon seedlings curl up and fail to grow? Today, we'll teach you strategies and operations so that before long, the watermelon seedlings can become lush and yield big, sweet watermelons.


### I. Pests and Diseases
#### Mosaic Disease
- **Symptoms**: Leaves show yellow-green mottling, shrinkage, and distortion, while the plant becomes short and weak. More alarmingly, it can cause watermelon fruits to deform and their sugar content to plummet! Caused by viruses, it spreads wildly when pests like aphids and whiteflies bite the plant.

#### Emergency Solutions:
1. Once a diseased seedling is found, pull it out by the roots immediately, seal it in a plastic bag, and remove it from the garden to avoid future troubles.
2. Hang yellow sticky traps in advance and spray imidacloprid to control aphids, cutting off the viral transmission chain.
3. Spray a 0.2% potassium dihydrogen phosphate solution once a week.


#### Red Spider Mites
- **Symptoms**: These tiny pests hide on the undersides of leaves, appearing as dense red spots the size of pinheads to the naked eye. They frantically suck the leaf sap, causing yellowish-white spots that quickly turn the entire leaf yellow and curled when severe!

#### Solutions:
1. Dip a cotton swab in soapy water diluted 50 times and gently wipe the undersides of leaves to eliminate both eggs and adults.
2. Use pyridaben or abamectin, diluting with water as per the instructions, and spray once every 3 days for 2–3 consecutive times to eradicate them completely.
3. Purchase predatory mites online and release them among the watermelon seedlings—they are the "natural enemies" of red spider mites.


### II. Nutrient Deficiency
Watermelon seedlings require abundant nutrients. Poor soil and single-type fertilizers can lead to yellow, thin, and soft leaves, delayed emergence of new leaves, slow plant growth, or even "stiff seedlings" that completely stop growing.

#### Fertilization Methods:
1. Seal soybean cake with water and ferment for 1 month, then dilute 20 times and water along the pot edge once a week.
2. Dissolve 5 grams of potassium dihydrogen phosphate in 1 liter of water, spray it on the leaves every 10 days, and simultaneously water the roots to promote both root and seedling growth.
3. Before planting watermelon seedlings, mix decomposed sheep manure or earthworm castings into the soil for long-acting slow-release fertility, ensuring the seedlings grow well.


### III. Insufficient Watering
Watermelon seedlings have shallow roots, fearing both waterlogging and drought. Dry and curled leaf edges, white and cracked soil surfaces, and dry soil below 2 cm when touched are signs of water deficiency.

#### Watering Methods:
1. Check the soil every morning and water thoroughly when the surface is dry until slightly渗水 (seeping) from the pot bottom, but avoid waterlogging.
2. In high-temperature summer, water once before 9 a.m. and once after 6 p.m. to prevent scalding the roots by watering at noon.
3. Spread a layer of straw or pine needles around the seedlings to reduce water evaporation and prevent weeds from competing for nutrients.