How much and how often should you generally water beans is 100 ml a day too little?

Watering requirements for beans vary depending on the growth stage, weather conditions, and soil type. Here's a general guide:

1. Seedlings: During the early seedling stage, beans require consistent moisture to support germination and initial growth. Water the soil around the seedlings regularly, keeping it moist but not waterlogged. Avoid overhead watering, as it can wash away the newly emerged seedlings.

2. Vegetative Growth: As the plants start growing vegetatively, they require more water. Apply water deeply and evenly to encourage deep root growth. Aim to water the plants about 1-2 times per week, depending on the weather conditions.

3. Flowering and Pod Development: During flowering and pod development, beans have the highest water requirements. Keep the soil consistently moist but not waterlogged. Water the plants regularly, providing around 1-1.5 inches (2.5-4 cm) of water per week.

4. Hot Weather: In hot and dry weather conditions, beans may need more frequent watering to prevent stress and wilting. Water the plants more often, but avoid overwatering.

As for the amount of water, 100 ml per day may be too little for mature bean plants, especially during hot and dry weather. It's important to consider the size and stage of the plants, as well as the soil conditions. If the soil is well-draining, you can water more frequently with smaller amounts. If the soil is heavy and retains water well, you may need to water less frequently but more deeply.

To determine if your beans need water, check the soil moisture by inserting your finger into the soil. If the top 1-2 inches (2.5-5 cm) of soil are dry, it's time to water.