Background and Research

 
 We are designing a system to automatically water a plant. We will program a sensor that will read values from the soil and it can determine the condition of the soil; dry, moist or over-saturated. We will also use a plant for the demonstration and do some research on it.

                              

                           Soil Hygrometer Sensor

 
           We are using a soil hygrometer sensor to sense the moisture content of the soil. It can be easily found here. We have gotten the following results back from a soil that has been watered a few seconds before the readings started being taken.

Initial Readings 

After a few readings that were not what were expected from the curve above, we decided on doing an extensive sensor reading test to find the different readings given off for the amount of water in the soil. We will then relate this value to the plant life we intend on using for the demonstration. We basically took ten cups about half way full of dry soil and took the readings for those cups. We average those values and we have our value for max dry soil. We then add water to make 5% water concentration for all ten cups. We will again take the readings for all ten and then average those out. We will keep doing this until we have 50% water concentration which will mean max saturation(1:1 ratio) and will give us the min reading we are looking for. We will then plot these points on a graph and use this curve to find an ideal water concentration for the plant we are going to use.

This project is also modeled around the arduino seen here.  This is what the second half of our project looks like. It is a solenoid valve that opens when current is passed through it.

Valve Circuit

Growing and Maintaining Aloe Vera

Introduction

Aloe Vera is the name of a very well known species of plant for its medical properties. Records of the plant date back 6,000 years to ancient Egypt, where this “plant of immortality” was offered as a burial gift to dead pharoahs (nccih). It has generally been used for cuts and burns, but recent discoveries also reveal that can also be used for “a variety of conditions, including diabetes, asthma, epilepsy, and osteoarthritis” (nccih). Currently, aloe vera is also a main ingredient in many skin products, such as lotion and sunblock. The plant’s medical properties are derived from a clear gel inside the plant’s leaves.

Aloe is a type of succulent, a plant species well adapted to living in hot and dry climates like deserts. Due to the severe change in temperature between day and night in deserts, succulents can sustain themselves in a variety of climates. Another adaptation unique to succulents is its ability to store water in its leaves, making them thick and fleshy (houseplants). Therefore, succulents don’t have to be watered much and are made even more durable.

Watering

The biggest danger to Aloe Vera, with regards to watering, is overwatering. Like most succulents, aloe likes a water that drains well. In the winter, water sparingly because water will not be drying very fast and in the summer, you can soak the soil, but make sure the soil dries out before watering again (aloeplant). Doing it in this method will prevent the roots from rotting, which will ultimately kill the plant. A drainage hole in the pot will significantly increase the drainage of water from the pot and hence, increase the plant’s lifespan.

Light

As aloe vera thrives in deserts, it would be best to recreate that environment by letting it soak up a lot of light, sunlight preferred. Sometimes it may not be possible to provide sunlight, such as in the winter and on cloudy days, so the plant should be supplemented with artificial light (aloeplant). If the plant is receiving too much light it will get sunburned, which is indicated by wrinkled and spotted leaves. If it is receiving too little, the leaves grow either downwards or outwards, but not upwards, the correct direction.

Soil

The best type of soil for aloe vera is one that dries fast. This is to prevent over watering the plant and infecting the roots. A good option is to purchase a specialized potting mix, or create one by mixing a normal potting mix with sand in a one to one ratio (hp). The addition of sand increases aeration and drainage, exactly what aloe’s roots need.

Temperature

Aloe’s natural habitat is the African desert, where temperatures get very hot during the day and drastically colder during the night. The minimum temperature aloe can withstand is 40˚F and the max is 85˚F (hp). During the winter, temperatures can drop lower than 40˚F so aloe should be brought inside the house.

Conclusion

Aloe vera is a durable and low maintenance plant because of its ability to thrive in harsh conditions and will survive as long as it gets infrequent watering, direct sunlight, and is potted in fast-drying soil.

Bibliography

Ejerome. “How to Care for Aloe Vera Plant.” aloeplant.info, 2011. Web. 7 May. 2015

United States. Dept. of Health and Human Services. National Institutes of Health.

“National Center for Complementary and Integrative Health.” National Center for

Complementary and Integrative Health. Dept. of Health and Human Services, Dec. 2006. Web. 7 May 2015.