Plant Dehydration - How to Detect and Treat It

Dehydration in plants (also known as drought stress) occurs when plants lack water is caused by either the roots being unhealthy and unable to absorb moisture, or the potting mix and soil not having enough. A plant’s ability to tolerate this stress varies from drought-tolerant species of indoor desert Cacti like the Golden Barrel and outdoor perennials like Guernsey Geraniums to drought intolerant tropical plants like Monstera and Ferns. Short periods of dehydration (forgetting to water for 1-2 days) are normally safe for most plant species, but longer periods can lead to discoloration, wilting, leaf burn, stunted growth, and even plant death. 

Dehydration is a serious condition as water is how plants remain upright, move towards the sun, and protect themselves from the sun's rays. And dehydrated plants will be unable to cool themselves by transpiration which then can lead their foliage to burn more easily from direct sunlight and the plant itself if exposed to a fire. 

The signs of plant dehydration include:

1. Crispy, brown edges on leaves where the leaf tissue dies off when the plant doesn’t have enough water to support it.

2. Curled or cupped leaves are the plants way to reduce the surface area from the sun during the day and need to compensate for the lack of water. 

3. Dull, matte, or translucent foliage on plants that normally vibrant and have deep rich color. This is not universal as plants like Silver Pothos (Scindapsus) and Philodendron have matte-looking leaves. 

4. Thin leaves that are normally thick could be a sign as thick leaves like the ones in Lithops are normally used for water storage. 

5. Drooping or shriveled leaves and stems can be a result of a lack of water pressure (called turgor), where cells collapse making the plant look wilted.

6. Leaves falling off are a way for plants to conserve energy when they’re too dry.

7. Quick bounce-back after watering is a sign that your plant was dehydrated.

8. Slow or stunted growth is a sign as your plant can’t take in nutrients or photosynthesize effectively without water.

9. Wilting during the day then bouncing back at night could be caused by losing water during the day faster than they can take it in, and then having enough to maintain proper structure at night when it's cooler. 

10. Potting mix or soil pulling away from the sides of the pot is a sign that the mix has hardened from being over dry which results in the plant having less access to water as the mix can no longer absorb and maintain it properly. =

Plant fact: Dehydrated plants like Lithops are less likely to survive the winter as they don’t have the water stored to survive while hibernating when their roots are asleep. 

If you’ve noticed any of these symptoms with garden or houseplants, or weird behaviors like cupping or only standing up at night, chances are your plants are dehydrated. This guide will help you learn about drought stress in plants as well as the signs of it, how it is caused, and ways to treat it. Here’s some jump links to help you get to the most relevant section.

Dehydration can be caused by:

1. Underwatering and poor watering practices

2. Poor Root growth or damage

3. Improperly sized pots

4. Dry potting mix

5. Environment (heaters, low humidity)

Underwatering occurs when plants don’t get enough moisture to perform basic functions like transporting nutrients or maintaining cellular structure. A common mistake is to rely entirely on a schedule rather than regularly checking the top 1-2 inches of potting mix to test whether it’s dry. 

You’ll also want to avoid underwatering as this also leads to dehydration when the plant cannot access enough. A good sign you have added enough water is when it begins to drain from the drainage holes in the bottom. 

Pro-tip: Try to make sure you’re watering the potting mix and roots, not the leaves or stems, as the roots are the part that will absorb the moisture. 

Roots are mainly responsible for water and nutrient uptake, so roots that are small or poorly developed will have a negative effect on a plant's ability to absorb water which is used to grow and sustain itself. 

The most common root issue is rot root where bacteria from trapped moisture begin rotting away at the roots. It can be found via a musky odor and discolored, mushy roots. If root rot isn’t the culprit and your plants are using the same pot or are planted outdoors with others, the other plants could be absorbing all the moisture and not leaving enough for the dehydrated one. The fix here is to plant the dehydrated plant in its own container or space where it can drink enough. 

While we want to give plants room to grow and thrive, you need to choose a pot that matches their current growth including making sure it is not too big or too small. Pots that are too big will hold too much water compared to the needs of your plant. As water remains stagnant in the potting mix, bacteria and fungi can take advantage of it and spread to your plants, causing root rot. A good rule of thumb is to pot your plant 1-2 inches larger in diameter than the root system. 

A pot that is too small can cause the plant to become root or pot bound, where the roots grow in a circular pattern that fills the container. This slows the distribution of water and nutrients as they must travel through the circling root system before reaching the plant, leading to stunted growth, wilting, and plant death. 

Once the potting mix becomes dry or has begun to shrink away from the edges of the pot, its ability to absorb and hold water decreases as it becomes hydrophobic. Because the potting mix has pulled away from the edges of the pot, the space created between the pot and the potting mix allows water to run through without touching the roots.

Some components in potting mixes, like peat moss and coco coir, will harden and shrink when dried out. For plants like Maranta Prayer Plants that like potting mixes with a high proportion of peat moss and coco coir, it will be easier to repot with fresh potting mix compared with rehydration. For plants like Succulents, Monstera or Pothos that usually like a potting mix with mediums that are easier to rehydrate like perlite or pumice, try bottom watering to rehydrate the mix for 1-2 weeks. Once the potting mix has expanded you can resume top watering. 

Dry potting mix will prevent nutrient absorption as plants depend on water in the soil to create a solution with their necessary nutrients and transport them into the roots (similar to how you don’t eat protein mix straight from the container but instead mix it with a liquid first). If the potting mix is dry or unable to hold water, no solution will be available and your plant will have a difficult time absorbing any nutrients which can lead to stunted growth. 

The environment your plant lives in, including temperature and humidity, can lead to dehydration if you don’t adjust your watering schedule to match. If your plant is placed near a heater, fan, or air conditioner in your home, it could dry out faster or retain too much moisture. If there is direct sunlight outside where they are planted or you live in a dry or desert region, the water will evaporate more quickly requiring more frequent watering. 

Pro-Tip: Avoid terracotta pots if you live in dry climates as they allow water to evaporate through their walls and can cause your potting mix to dry out too quickly. 

If you suspect dehydration, here are some steps you can take to treat it. 

If you have been underwatering, increase your watering frequency and try to stay consistent by setting reminders on your phone to check the top 1-2 inches of soil and to water. 

Trim leaves that are brown and crispy so the plant can focus on growth rather than leaf recovery from irreversible damage. 

Try watering from the bottom instead of the top to rehydrate the potting mix. 

1. Fill a bowl with water and place the plant (pot and all) inside.

2. Let it sit for 3-4 hours each day until the potting mix feels moist. 

3. Once the mix expands to the edges of the pot and leaves unfurl, you can stop. 

This can take 1-2 weeks and will vary by the makeup of your potting mix. You don’t want to leave the pot in the water all day, as that can lead to root rot from fungus or bacterial growth in the standing water. Once the potting mix has expanded back to the edges of the pot, you can start watering from the top again.

Overly dried-out potting mix high in peat moss or coco coir can become hydrophobic, so one option is to remove the plant, carefully clean the roots, then repot in fresh potting mix selected based on the plant's type. Do not try to compensate for dehydration if you forget to water by choosing a potting mix that holds onto more water as the potting mix should be matched to plants needs, not us wanting more moisture in them. 

If increasing watering frequency does not help or your plant's root system is damaged, small or absent, try growing in a water culture (hydroponics) if your plant can adapt. 

Some plants like Maranta and Monstera can be grown directly in water rather than in a potting mix. Choose a vase or pot that can hold the root ball and place the plant inside with enough water to cover the roots. Within 2-3 weeks, you should see root growth and improvements in coloration. From there you can keep them growing hydroponically or plant them in a new pot.

If the plants are near your vents, a heater, or air conditioner, move them further away so they can remain at room temperature and the potting mix can have a natural way to maintain and release moisture. If moving the plant is not an option, water more frequently in a dry or heated space and less frequently in a cooler one.

If your plants dehydration is from root rot or your plants being root or pot bound (roots growing in a spiral and overfilling the pot), you can treat it directly. 

If you suspect root rot, remove your plant from the pot and:

1. Trim any rotting or dead roots with sharp, sterilized shears. 

2. Treat the roots with a hydrogen peroxide solution (3 parts water to 1 part peroxide (do not do more than 1 part peroxide as this is already a strong dose)) or plant-safe fungicide to make sure all bacteria and other potential threats are washed away. 

3.  Re-pot in a new well-draining potting mix, ensuring the pot has holes in the bottom for proper drainage.

For already root or pot-bound roots:

1. Remove your plant from the pot

2. Use sterilized shears to prune the roots if possible or make 2-inch cuts into the root ball to interrupt the circular growth pattern and encourage the roots to spread out when regrowing. 

3. Repot in a container at least 1 size larger with fresh potting mix

Dehydration is one of the easiest plant issues to prevent. It is a matter of changing the location of plants, their environment, or your watering habits. 

Here’s a few tips to help prevent it: 

• Choose the potting mix for your plant type and pot based on your plants root system. Some plants, like the Musa (and our signature Bronana) prefer a deep pot while others, like the Maranta, prefer wide shallow dishes. 

• When receiving new plants, remove them from the pot they arrive in and repot with fresh potting mix and a properly sized pot. This ensures you have complete control of how your plant stays hydrated and gets nutrients. 

• Set reminders on your phone for when to water so you never miss a hydration session.

• Check the top 1-2 inches of the potting mix every 5 to 7 days. 

• Make sure your plant is kept out of drafts, heaters, air conditioners, and direct sunlight (unless direct sunlight is required) to keep the potting mix at natural temperatures and cycles.

Plant dehydration is common and nothing to worry about, as long as you detect it and the cause before your plant is affected. Treating it is a matter of repotting the plant, adapting its environment, and altering its watering schedule.