Did you know you can kill some plants just as easily from too much water as not enough water? It’s one of the more common mistakes for new gardeners!
The confusing thing - a plant that is being overwatered looks just like a plant that does not have enough water! Wilting, brown leaf tips, yellowing leaves, and leaves that fall off the plant!
It can be confusing and disheartening to find a dead plant with a soggy soup in the bottom of the pot when all you did was give a wilting plant what you thought it needed!
Factors That Can Cause Overwatering
Knowing a few things about how plants respond and about their environment will be your first step in identifying and preventing overwatering!
Soil Type
Soil type makes a huge difference in the frequency you will be watering your plant. In sandier soils and soil that drains very well, you will need to water your plants more frequently, as rain or irrigation drains away from the soil quickly.
Heavier clay soils do not allow the water to percolate as quickly and will hold the water in place for a longer time. Adding water to clay soils too frequently can cause big problems.
Plants grown in containers depend upon you to supply the proper amount of water. Make sure the pots you use have holes in the bottom, so excess water can drain away from the soil if too much water has been applied. If there is a tray to catch the excess water, simply pour the excess off as it drains through the soil so the plant is not sitting in water.
Air Humidity
Especially for indoor plants, and also for outdoor plants, the amount of moisture in the air will affect how fast plants use water. High humidity means plants are not losing too much moisture through their leaves; both through transpiration and evaporation. So they will not need as much soil moisture at this time.
Time Of Year
Summer and hot temperatures will mean plants need more soil moisture! This is when a good 3-4 inch layer of mulch over their roots not only keeps them cool but also prevents a significant amount of evaporation. Keeping moisture where they need it most! Using a light layer of mulch on top of the soil for your container plants is also a good idea!
During cold dry winters, plants also need moisture in the ground. Harsh cold temperatures lock up moisture as ice and do not allow roots to absorb the moisture they need. Even if they are not using as much moisture to grow and flower, dry wind, and cold can leech moisture through their stems and foliage - as is the case with evergreens and broadleaf evergreens. Because they still have their foliage, they will suffer windburn and frostburn if they are not adequately hydrated at the roots.
Solution? Always ensure the soil has adequate moisture for broadleaved evergreen and evergreen plants - right up until the ground freezes. Using mulch will delay the ground from freezing as quickly allowing the plants to continue using soil moisture for a longer period of time.
- Little to no rainfall
- No snow or no consistent snow cover (which also insulates the roots like a blanket and keeps soil moisture locked away
- Above freezing and plants are exposed to dry northern winds
You can further help these plants by including a 3-4 inch deep layer of mulch and a coating of anti-desiccant like Wilt-Stop to prevent foliar moisture evaporation.
Plants In Containers
Houseplants indoors, and plants in containers and pots outside, need to be checked for moisture more often during heat (daily during the summer) and at least twice a week indoors.
Factors that will make containerized plants need more or less water include:
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Time of year - Houseplants will not grow as much during the winter, even indoors, so will not need as much watering. This varies a bit if:
- The plants are in small containers
- You keep your home very warm or on the cooler side during the winter
- Your air in general is very dry or you run air humidifiers
- If your plants have good drainage
- The type of soil in the container (fast-draining or water-holding)
- Temperatures & Sun
- More moisture is needed in the summer months and during prime growth, prime flowering, and peak fruiting seasons
- Less water is needed if plants do not have good drainage holes. This allows excess water to pool in the bottom. Therefore, the surface may feel wet, while the bottom is a swamp.
- Plants in direct sun will transpire more moisture and the soil will evaporate faster
- Plants in more shade or indoors will not use as much moisture or lose as much through their leaves. Again if your environment is dry/arid, or your home's air is very dry, it will affect soil moisture.
- Type of Pot/Container
- Small pots will dry out faster, larger pots not quite as much (unless in high heat, full sun, or have large drainage holes). Avoid using materials in the bottom of your container like rocks to ‘add drainage’.
- Plants with large drainage holes will shed excess water fast
- If you’ve let the soil dry out and there are gaps along the side of the pot and soil. Water will simply rush right through and the soil and roots will not have a chance to soak any up. Over-dry soil will become hydrophobic, and simply let the water flow on by, like water off a duck's back! Repeated deep watering, or soaking the entire pot if able is the only way to ensure the entire root system has been fully re-hydrated. It is best to never let them get to this point!
Remember the environment, and soil type in your pot also factor into how fast it uses water.
- The Type of Plant
- Some plants need higher moisture or consistent moisture - requiring more frequent moisture checks.
- Some plants thrive in lower moisture levels - like Succulents, Cactus & Citrus. So they will need less frequent watering but deep watering to ensure the entire soil ball is saturated sufficiently (these plants also need excellent drainage and soil that doesn’t hold onto water).
- Other plants can hold water in their roots, stems, or leaves or are just hard-to-kill plants that will forgive you if you over or under-water them.
- Mulch or Other Soil Coverings
- If you use moss or mulch over the soil - congrats! Your plant won’t need as much moisture.
- Plants with bare and exposed soil will evaporate moisture much faster
Knowing your plant, and knowing what soil and moisture levels it prefers, is your top priority. Do not mix different plants that have vastly different soil moisture needs - one of them isn’t going to thrive!
Why Don’t Plants Like Lots Of Water?
So, we know too little water is bad, but why is too much of a good thing also bad?
In short - Food, Water & Oxygen!
Some plants are naturally adapted to soggy soils that do well at the water's edge or boggy wetland areas. However, most of the plants you are planting inside and outside your home are not water plants. Unless they are in a pond, their roots are not suited for constant water presence, especially if it is anaerobic and has no access to oxygenation - leading to smothered roots - literally!
Roots are not dumb - they will actively grow wherever they find food, oxygen, and water. Roots do not always just grow out in all directions all the same distance from the plant as you might think.
If the roots are waterlogged, they will not have enough oxygen. This can lead to stress or root rot, which will weaken the plant, or cause it to die. The plant roots may respond by growing closer to the surface and away from the areas that remain wet. (as in the case of Bald Cypress which can form ‘knees’ that act as air vents for their roots!) If the feeder roots die due to suffocation or drying out, the plant cannot take up water and food.
Ironically, if roots grow close to the surface to escape the negative effects of overwatering, your plant will be more vulnerable to times of drought. Check out How to Protect Gardens From Heat Stress in our Garden Blog. You want your plants to firmly establish themselves in your garden with deeper root systems.
Too much water at the bottom of pots and containers also leads to an anaerobic environment that is a breeding ground for bacteria and disease. These eat away at the roots, causing rot and more for the bacteria to feed on and you get smelly, mucky roots and a dead or dying plant.
New Plants Versus Established Plants
Newly planted plant materials need you! Don’t install new plants and go on vacation. You need to be there for them! Check out how to start your plants off on the right foot from the moment you receive them from NatureHills.com in our Planting Guide and Support!
Newly planted bareroot or container-grown plants will need a very deep soaking the day you plant them, and more frequent watering to keep the plant evenly and thoroughly moist enough to start making new roots into the soil they were planted into. That is the key! New plants also need immediate moisture access until they can grow new roots!
Plants all respond a bit differently, and the timing will depend upon the temperature and weather at planting time. But being attentive to the water needs is crucial for the first couple of weeks!
Once they are established (usually 4-8 weeks after planting/transplanting) you can ease up on lugging that hose around. After that, your plants should only need you to continue to water regularly if:
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No rainfall, or less than 2 inches of rain for the entire first growing season
- It feels dry a few inches below the soil
- It’s been excessively hot/it's summer
- Your plant is in full flower/developing fruit
- It’s in full sun all-day
- There is no mulch over the soil surface
- Drainage type - sandy = fast draining/organic = more moisture holding
- Condition of the soil
- If your plants are pot-bound (less soil and more roots = less water-holding capacity)
- You have a very large plant in a very small pot (It's going to go through moisture fast)
- You are finally taking that vacation!
After a couple of weeks or you are through the plant's first very hot summer, you will notice that your newly planted plants need less frequent watering. That’s because the plants have established some by growing new roots into your soil, finding their own food, oxygen, and water themselves!
Yay! After they have established, your plants become less dependent upon you to supply any additional water.
*Remember:
Don’t rely on sprinklers or lawn irrigation to thoroughly water your trees, shrubs, and perennials. Sprinklers are for kids and lawns - not deeply rooted plants! Check the soil moisture frequently to know how often your plants will need additional water in their environment. Water without any hose nozzle - just the open hose end, and apply water to the root area only, keeping the plant foliage dry. Placing the water at the roots is best, and allows it to soak in deeply, exactly where it is needed. Keeping the foliage dry lessens the chance of foliar disease.
How Often Do You Water Older & Established Plants In Your Yard?
It is almost impossible to make a blanket statement about watering with so many variables like soil types, climate, and temperatures.
Most older and established trees will not need you for a lot of help unless Ma Nature gets extreme.
With that in mind, watch your weather patterns and if you are not seeing rainfall for longer periods than is normal for your area (heatwaves and drought) then it would be worth your while, to keep your plants growing stress-free, by dropping a hose under your Birch tree or other type of plant that might need some additional soil moisture in your area. Stress-free plants are healthy plants and able to better resist insects, disease, and the effects of other external influences.
How To Tell If Plants Need Water?
So just how are you supposed to tell if your plant needs water? Is there a right way to water?
Guess what… it's not rocket science! In fact, there's no science needed! (Or math either!)
The Lift Test
If it’s a smaller container or planter - Pick it up! The lift test is a fast method to tell if your potted plants are watered well, dry as a bone, or soaking wet!
- An especially light-as-air pot is in desperate need of water now! Soak it or water it well and check again.
- An especially heavy plant means you better check the bottom to see if the drainage holes are blocked.
Follow Your Nose!
Are you seeing lots of fungus gnats? Does the soil smell like rotting compost or that salad you forgot about in the fridge for a few weeks? That means your soil is rotting and you need to repot to save your plant.
Use Your Finger!
The Finger Test is an indispensable, free, and reliable method of knowing if your plant needs water or not! Simply stick your finger into the soil up to the 2nd knuckle around the roots. Feel the soil. If moist – skip watering that day. If dry – then give a good drenching drink that day! For containers, it’s the same but ensure they’ve drained out any excess and that it didn’t just rush right through without stopping. You can also see how it’s done and more on the NatureHills.com YouTube Channel!
Key Take-Aways
To sum up, here are the main points for you to remember about watering plants the right way!
- Use the Finger Test method to feel the soil at the roots - if it is moist to the touch a few inches under the surface, check again tomorrow or later that week. If it is dry - soak it and check again tomorrow.
- Use 3-4 inches of arborist or organic bark mulch over the entire top layer that extends over the roots around your plants - without mounding any mulch up against the plant crown or stems of your perennials or shrubs, or over the trunks of your trees.
- Ensure containers have good drainage, and the right soil for that type of plant, and you check each time before watering to ensure they are getting enough.
- It’s better to water your new and established plants longer, and less frequently, rather than for short, frequent “sprinkles” that only wet the top layer of soil or run off the hydrophobic surface.
- You also don’t want your roots to grow shallowly near the surface where they can dry out quicker and get baked in the sun or iced in the winter. A larger volume of water applied to the entire root system will allow those feeder and anchor roots to continue to grow down deep into the earth, where moisture may be more readily available.
- Also, water at the roots of your plants, and not the leaves or flowers! You’ll keep your plants cleaner and less susceptible to foliage problems!
- Never just apply the same amount of water each time or just water on a specific schedule. Plants' needs are as variable as we are! We don’t always eat or drink the exact same amount at exactly the same times of day! Your plants won’t either. Check to see if they need water and only water enough to soak the root system and soil, then let the excess drain away right away!
The Right Amount Of Water Is Where It’s At!
Unfortunately more isn’t always better! It’s a delicate balance but knowing what to look for and how to water your plants the right way.
Did you know Nature Hills Nursery has a fantastic root system support that works for your landscaping plants, container plants, and houseplants alike? Nature Hills' own Root Booster is a beneficial symbiotic mycorrhizal fungal support that provides lifelong assistance to feeder roots of plants. Better allowing them to take up moisture, break down nutrients, and aid root health for the life of the plant! Simply rake into and water into the soil around established plants, or sprinkle a packet around the planting hole when installing new trees, shrubs, and more! Pick up some today!
Head over to NatureHills.com for more information about caring for your new plants and trees, caring for your container plants and houseplants, and all their after-planting care like pruning, division, and fertilization!
Happy Planting!
