Do Rain Affect Outdoor Hydroponic Plants?

Sept. 15, 2022

Do Rain Affect Outdoor Hydroponic Plants?

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You may have seen those spindly little plants with their roots dangling in the air and wondered, "What on earth are those things?" Those plants are growing in a hydroponic system, and they're thriving! Hydroponics is a type of gardening that uses nutrient-rich water instead of soil to grow plants. Because hydroponic gardens don't rely on soil, they can be set up just about anywhere—including indoors. And yes, this means that you can grow hydroponically in the rain!

One common misconception about hydroponics is that plants are grown using only water. While it's true that hydroponic gardens don't rely on soil, there is more to it than just water. Plants need sunlight and nutrients to grow, and you must carefully balance these elements for the plants to thrive.  

Too much sunlight will scorch the leaves, the too little sun will cause the plant to become etiolated (i.e., stretchy), and lack of nutrients will cause the plant to fail to produce fruit or flowers. A properly balanced hydroponic garden will have ample sunlight and nutrients for the plants to grow healthy and strong—rain or shine!

The good news is that some tips and tricks can help you learn how to grow outdoor hydroponic plants in the rain. 

Is Rainwater Good for Outdoor Hydroponics?

Many people believe that rain's downsides are the effect it can have on outdoor plants. However, many people don't know that rainwater can be beneficial for outdoor plants, especially hydroponics. 

Here we'll discuss some benefits of rainwater for outdoor hydroponics and explain why you should consider collecting rainwater for your plants.

  1. One of the most significant benefits of rainwater for outdoor hydroponics is it's free! Collecting rainwater is a great way to save money on your water bill, and it's also a great way to conserve water. 
  2. Rainwater is also environmentally friendly because it reduces your carbon footprint.
  3. Rainwater is naturally soft. This means it does not contain any salts or minerals that can build up in your system and harm your plants. Rainwater is also relatively neutral in pH (5 to 6), essential for maintaining a balanced growing environment. 
  4. Another benefit of rainwater for outdoor hydroponics is that it's typically very clean. When rain falls, it picks up pollutants and contaminants from the atmosphere and deposits them on the ground. However, when you collect rainwater in a barrel or tank, those pollutants and contaminants are left behind, leaving you with clean water for your plants. 
  5. Rainwater is also a great source of nutrients for your plants. As rain falls, it picks up minerals and nutrients from the soil and deposits them in the water. When rain falls, it picks up nitrogen, potassium, and phosphorus from the atmosphere. When you use rainwater to water your plants, the roots absorb those nutrients and help nourish the plant. 
  6. Rain water contains more oxygen than tap water. This is because rainwater has a lower dissolved solid content, which allows more oxygen to dissolve in the water. This extra oxygen can help promote healthy root growth and overall plant health.
  7. Rain water is free from chlorine, and other chemicals often added to municipal water supplies. These chemicals can harm delicate plant roots and even inhibit plant growth. You can avoid these potential problems using rainwater and give your plants the best possible chance to thrive. 
Related:
Why You Should Consider Outdoor Hydroponic Growing
4 Common Types of Outdoor Hydroponic Systems

How Does Rain Affect Outdoor Hydroponic Plants?

Rainfall impacts hydroponics in different ways; it can change water levels, pH balance, electrical conductivity, reservoir water temperature, and nutrient levels.

  1. One of the most immediate effects of rain on an outdoor hydroponic system is the influx of water into the system. This can quickly change the water level in your reservoir, which can lead to problems with your pumps or other automated watering systems. Additionally, this sudden change in water level can shock your plants, causing them to wilt or even die. You can avoid this by ensuring your reservoir is covered to prevent rainwater from getting in. 
  2. Another issue with rainwater is that it can contain high levels of pollutants such as heavy metals, bacteria, and viruses. These pollutants can be harmful to both humans and plants. Therefore, it is important to test the rainwater's quality before using it in your hydroponic system. 
  3. Another potential problem with rainwater is that it can be acidic if rainwater picks up carbon dioxide from the atmosphere, which makes it slightly acidic. If the pH of your hydroponic system is not properly balanced, this acidity can harm your plants.
  4. Another issue that rain can cause is a change in your reservoir water's pH and electrical conductivity. These changes can be caused by pollutants being washed into your system from the rain or by adding fresh water to your existing solution. Either way, these changes can stress your plants and prevent them from properly absorbing nutrients. As a result, you may see yellowing leaves or stunted growth. You can save your plants by regularly testing your reservoir water's pH and electrical conductivity and making adjustments as needed. Click here if you require a meter to test pH, EC, TDS and temperature of the reservoir water.
  5. Finally, rain can also cool down the temperature of your reservoir water and your plants. During the hot summer months, it can lead to heat stress in your plants. In extreme cases, heat stress can cause leaves to curl and flowers to wilt. You can protect your plants from heat stress by covering your reservoir to prevent evaporation and using a water chiller to control the temperature of your reservoir water.

Are There Any Nutrients in Rainwater That Outdoor Hydroponic Plants Can Use

Yes, rainwater is a great source of nutrients for outdoor hydroponic plants. As rain falls, it picks up minerals and nutrients from the soil and deposits them in the water. When you use rainwater to water your plants, the roots absorb those nutrients and help nourish the plant. 

What Nutrients Are Added to the Hydroponic System by Rain?

Some of the minerals and nutrients that rainwater can add to your hydroponic system include: 

  • Nitrogen is an essential nutrient for plant growth and often lacking in hydroponic systems. Rainwater can help replenish your system's nitrogen and encourage healthy growth. 
  • Phosphorus is another essential nutrient for plant growth. It helps to promote root development and encourages strong stems and leaves. 
  • Potassium is essential for proper plant metabolism and plays a role in many processes, including photosynthesis, water uptake, and disease resistance. 
  • Calcium is important for cell wall development and strengthens the plant's structure. 
  • Magnesium helps with photosynthesis and chlorophyll production. 
  • Sulfur is important for protein synthesis and helps to give plants their green color. 

Related: 13 Nutrients Required for Hydroponic Plants

What Is the PH of Rainwater, and How Does It Affect Plants

The pH of normal, clean rain averages between 5 and 6. It may be more acidic when it combines with sulfur dioxide or nitrogen oxides. If the rainwater you collect has a higher pH, you can adjust it by adding a little bit of vinegar or lemon juice to the water.

The pH of rainwater is important to consider because it can impact outdoor plants' growth. If the pH of rainwater is too high or too low, it can cause problems for plants. For example, if the pH of rainwater is too high, it can make the soil too alkaline for plants to grow. On the other hand, if the pH of rainwater is too low, it can make the soil too acidic for plants to grow. 

Rainwater can affect outdoor hydroponic plants depending on their pH level. It is essential to test the pH level of rainwater before using it to water your plants. Most plants prefer a neutral or slightly acidic environment, with a pH between 6.0 and 7.0. If you are having trouble getting your plants to thrive outdoors, testing the pH level of your rainwater may be a good place to start.

How to Protect Your Outdoor Hydroponic Plants From Heavy Rain

What happens when bad weather threatens your plants? Here's how to protect your outdoor hydroponic plants from heavy rain.

  1. Ensure your system is draining appropriately so that water doesn't pool around your plants and roots.
  2. If possible, bring them inside. If you have the space, get your plants inside until the storm passes. This is especially important if the forecast calls for hail or high winds.
  3. Cover your plants with a tarp to protect them from the rain if you can't bring them inside. Ensure the tarp is secured so it doesn't blow away in the wind.
  4. Move them to a sheltered area. If you have a porch or another sheltered area, move your plants there until the rain stops. Click here to buy if you need a suitable shelter for your plants.
  5. Prune them back. If your plants are getting too big and are at risk of being damaged by the weather, prune them back to help reduce wind resistance. 
  6. Check the roots. After heavy rain, check your plants' roots to ensure they're not waterlogged. If they are, give them a chance to dry out before watering again.

Heavy rains can be tough on outdoor hydroponic plants, but with a little preparation, you can keep your plants safe and healthy. So next time a storm is brewing, take some time to protect your investment—your plants will thank you for it!

Related:
Successful Hydroponics in Any Climate
Timers for Successful Hydroponic Gardening

Bottom Line

Rainwater can be a great resource for outdoor hydroponics, and it has many benefits. If you're looking for a way to save money on your water bill or if you're looking for a clean, nutrient-rich source of water for your plants, consider collecting rainwater the next time it rains.

Just remember to keep your plants in an area with good air circulation, ensure they have good drainage, and water them as needed.

While rain is generally good for traditional gardens, it can pose some challenges for those who grow hydroponically. By being aware of how rain can affect our outdoor systems, we can take steps to mitigate the impact and keep our plants healthy and happy. Understanding how rain affects your garden and taking steps to protect your plants can ensure that your garden will thrive no matter what the weather brings. So get out there and start growing!

Thank you for reading!

Also, read:
The Difference Between Kratky and DWC Hydroponic Systems
7 Cost-Effective, DIY Hydroponics for Home
How to Choose the Right Hydroponic System for Your Needs?
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