Preventing mortar from drying out too quickly is essential for ensuring proper hydration and strength development. Here are some tips to help slow down the drying process:

1. **Use the right mortar mix**: Choose a mortar mix with a longer working time or slower drying time, such as Type S mortar or mortar with a high lime content. These mixes are designed to remain workable for longer periods, giving you more time to lay bricks without the mortar drying out too quickly.

2. **Keep materials cool**: Store bags of mortar and dry mix in a cool, shaded area to slow down the curing process. Avoid exposing materials to direct sunlight or high temperatures, as this can accelerate drying.

3. **Use cold water**: Mix mortar with cold water instead of warm or hot water, as colder water slows down the hydration process and extends the working time of the mortar.

4. **Mix in small batches**: Mix only as much mortar as you can use within a reasonable timeframe to prevent excess mortar from drying out before it can be applied. Mixing smaller batches as needed ensures that the mortar remains fresh and workable.

5. **Add a mortar retarder**: Consider adding a mortar retarder additive to the mortar mix to extend the working time and slow down the drying process. Retarders are available in liquid or powder form and can be mixed into the mortar according to the manufacturer's instructions.

6. **Keep the work area damp**: Wet down the bricks and substrate with water before applying mortar to prevent them from absorbing moisture from the fresh mortar too quickly. Keep a spray bottle or hose nearby to mist the surface periodically as you work.

7. **Cover exposed mortar**: If you need to take a break or pause during construction, cover exposed mortar with plastic sheeting or damp burlap to prevent it from drying out too quickly. This helps maintain moisture levels and prolongs the working time of the mortar.

By following these tips and techniques, you can help prevent mortar from drying out too quickly and ensure that you have enough time to lay bricks properly without compromising the strength or quality of the finished wall.