Watering plants properly is one of the most important aspects of growing healthy, thriving container plants. While there are some general guidelines, how much water your plants need can vary quite a bit based on pot size, plant type, environment and more. In this comprehensive guide, we’ll walk through the key factors in determining the right watering approach and amount per pot size for your container plants.
Why Proper Watering Matters
Before diving into specifics, it’s worth covering why proper watering is so crucial for potted plants. If you consistently under-water your plants, they will become stressed, stop growing, and potentially die. Over-watering poses similar risks – the roots can rot leading to very poor plant health.
Additionally, inconsistent watering that fluctuates between very wet and very dry spells stresses plants out. They thrive on consistency.
Getting the right balance requires consideration of pot size, soil type, plant type, temperature, humidity and growth stage. When dialed in correctly, it allows the plant to uptake just the right amount of water and oxygen through the roots.
General Rules of Thumb for Water Amounts
While specific amounts will vary based on many factors, there are some general rules of thumb to use as starting points:
- Seedlings – Water lightly, just 1-2 tablespoons as needed to keep soil moist. Avoid saturating.
- Small pots (<1 gallon) – Water when top inch of soil is dry. Add enough water for it to seep out drainage holes.
- Medium pots (1-5 gallons) – Water when top few inches are dry. Add water until it drains from the bottom.
- Large pots (>5 gallons) – Water when several inches deep feel dry. Add water until at least 20% drains out.
Adjust amounts based on plant needs and environment Larger, thirstier plants need more water more frequently Hot, dry, or windy conditions increase water needs.
These are just general guidelines, but provide a good starting point. Next we’ll cover the key factors that determine exact watering needs.
Key Factors That Determine Watering Amounts
There are several variables that impact precisely how much water your potted plants need:
Pot Size
Perhaps the most obvious factor is the pot size itself. The more soil volume, the more water needed to thoroughly moisten the entire root zone. Here are some typical starting points based on pot size:
- Seedlings or propagations – 1-2 tablespoons
- 2” seed starting pots – ~1/4 cup
- 4” nursery pots – 1/2 to 3/4 cup
- 1 gallon pots – 1-1.5 cups
- 3 gallon pots – 3 cups
- 5 gallon pots – 4-6 cups
- 7+ gallon pots – 6-8+ cups
These volumes allow for roughly 10-20% runoff, indicating thorough watering.
Plant Type
Certain plant varieties and species are naturally more thirsty than others. Warm season annuals like tomatoes, peppers, zucchini, and cucumbers need frequent watering to support growth. Quick growing leafy greens also want consistently moist soil.
Succulents, cacti, and desert-adapted plants need far less frequent watering. Over-watering these types of plants can easily kill them. Know your plant’s specific preferences.
Growth Stage
Younger plants need less water more frequently. Their small, unestablished root systems absorb moisture quickly. At the same time, over-saturating the soil can lead to damping off disease. Add small amounts of water often.
Mature, fruiting plants need the most water to support peak growth. Their large root systems allow for less frequent yet deeper soakings.
Environment
Hot, dry, windy conditions cause moisture to evaporate faster from soil and plant leaves. This leads to quicker drying and increased water needs. Cool, humid climates reduce evaporation and the frequency of needed watering.
Likewise, full sun exposure compared to shade changes moisture loss. Observe your plants closely to see impacts of environmental factors.
Soil Type
Soil composition affects its ability to hold and release moisture. Sandy and rocky soils won’t retain water well and drain quickly. They need more frequent watering for high-drainage loving plants.
Loamy soils with lots of organic material hold moisture much better. They can go longer between thorough waterings. Know your soil composition!
Signs It’s Time to Water Based on Pot Size
Rather than sticking to a rigid schedule, observe the visual signs it’s time to water based on pot size:
- Seedlings & small pots – Surface is dry and cracked
- 1-3 gallon pots – Surface 2” deep is dry
- 5-7 gallon pots – Surface 4-5” deep is dry
- 10+ gallon pots – Surface 6”+ down is dry
For larger pots, the weight provides clues too. Pick up the pot to feel its weight when fully watered. When it feels much lighter, it’s time to water again.
The leaves themselves will also indicate needs. If they start to droop, curl, or turn color then the plant likely needs water. Pay close attention when temperatures rise.
Best Practices for Watering Different Sized Pots
Beyond how much water, technique is also important:
Seedlings & Small Pots
- Water gently to avoid splashing
- Ensure even coverage without washing out soil
- Stop before saturated to prevent damping off
1-5 Gallon Pots
- Add water until it flows from drainage holes
- Allow to fully soak in, then repeat until thoroughly moist
- Lift pots to ensure no dry pockets remain
7-15+ Gallon Pots
- Water until 20-30% flows from the bottom
- Soak the entire root ball and center of the soil
- Repeat watering in 10-15 minutes
All Pot Sizes
- Water in mornings to prevent overnight moisture
- Add moisture meters to help gauge dryness
- Adjust amounts based on seasonality
Following these best practices ensures your potted plants get adequate moisture without risk of under or over-watering.
Recap – Determining Watering Needs Per Pot Size
Properly watering potted plants requires considering many factors:
- Pot size – Smaller pots need less water, bigger pots need more
- Plant variety – Some plants naturally more thirsty than others
- Growth stage – Younger vs. mature plants
- Climate – Hot/dry increases water needs
- Soil type – Sandy soils drain faster than loamy soils
- Visual signs – Leaf and soil clues
While general guidelines provide starting water amounts, observation and adjusting as needed is key. Aim to create consistently moist yet well-drained conditions optimized to each plant’s needs.
Over time, you will dial in the ideal amounts and frequencies. Proper watering is crucial for helping container plants thrive, so listen closely to what they need! Consistency is key when it comes to watering potted plants.
This is the big question of all amateur gardeners!
Too much water can rot the roots of some plants or bring various diseases.
Not enough water does not allow the fruit to grow well or worse, the plant dries out and can die.
A magic number to remember: 2.5
Either 2.5 cm or 1 inch of water per week for a plant.
Obviously, all plants have different needs, for example tomatoes usually require more and garlic much less. Excellent books on gardening, like that of Bertrand Dumont, will give you a general indication, little, average, a lot of water. See our summary table at the bottom!
2.5 cm, ok, but in liters? … and what do we mean by 2.5 cm of water? Where is this 2.5 cm?
In fact, this is an average of 2.5 cm of water per week for a plant, which is actually 2.5 cm of water (in height) multiplied by the approximate area of 30 cm by 30 cm. cm. This gives us 2250 cubic centimeters of water, or 2.25 liters of water a week! This is a lot of water, you will probably want to water in 2-3 times with less water at a time.
Many plants in a pot or kitchen garden square?
No need to calculate for all plants individually! It’s quite simple, we simply calculate the total area of pot, approximately, or the kitchen area (ex .: kitchen garden square). Examples of calculations below!
Watering Basics #2: How Much Water To Add To Your Container
FAQ
How much should I water my plants based on pot size?
If you’re hand watering it’s recommended to water in 5-10% of your soil volume. So for your 15 gallon pots that would be 0.75-1.5 gallons per pot. You can tell if they need water by lifting up your pots and feeling the weight.
How much water should I give my pot plant?
-
PlantInhttps://myplantin.comTips For Watering Cannabis Plants – PlantInDuring the flowering stage, the root system is already sufficiently developed. Even though it can receive a certain amount of water from the soil at this stage,
-
Proven Winnershttps://www.provenwinners.comHow to Water Plants & Flowers in Pots – Proven WinnersDifferences in pot and plant sizes will impact how quickly a pot dries out. When you water be sure to moisten the entire root zone. In other words, water until …
-
Greg Apphttps://greg.appHow Often Should I Water My Marijuana? – GregJun 15, 2024 — Watering Frequency Throughout the Growth Cycle … Cannabis seedlings are like infants, delicate and in need of gentle care. Keep the top inch of so…
-
The Home Depothttps://www.homedepot.comHow to Repot a Plant – The Home DepotFeb 12, 2024 — Make sure to add enough water but not too much to avoid rotting the roots. Your new pot may have a saucer at the bottom for draining water. After yo…
-
MicroDripshttps://www.microdrips.comHow much water for my plants? – MicroDrips BlogMay 22, 2019 — Either 2.5 cm or 1 inch of water per week for a plant. Obviously, all plants have different needs, for example tomatoes usually require more and gar…
How much water for a 15 gallon pot?
| Container | Water volume | Run Time |
|---|---|---|
| 1 Gallon | 3 gal | 3-4 Hrs |
| 3 or 5 Gallon | 5-7 gal | 3-4 Hrs |
| 15 Gallon | 15-20 gal | 3-4 Hrs |
| 25 Gallon | 20-30 gal | 3-4 Hrs |
How much water do you need for a small pot?
Suppose you want to water your plants twice a week. That would be 1 inch X twice a week = 2 inches of water. Three times a week would be 3 inches of water. The calculator will still give the weekly and daily requirements. Since any pot is much smaller than a garden or raised bed, using gallons or liters wouldn’t make sense for smaller pots.
How much water does a pot plant use?
In a sizable outdoor operation, the plants can suck up something on the order of a billion liters of water per square mile over a growing season. Some estimates suggest that pot plants use six gallons of water per day per plant over the summer. For reference, it takes about four gallons of water to run an energy-efficient dishwasher once.
How much water does a plant need?
Watering your plants properly is crucial for their health and growth. While there are general rules of thumb, how much water your plants need can vary based on the pot size, growth stage, environment, and more.
How much water does a 5 gallon pot require?
A 5 gallon pot requires approximately 1-1/4 gallons of water. The actual amount can vary depending on factors such as soil mix and how dry the pot is allowed to get. To water the pot, the speaker puts it inside a larger pot and waters both from the top and the bottom. Once the soil has absorbed all the water it can, the pot is left to sit for 5-10 minutes before being drained as much as possible.
How much water should be put in a 6 inch pot?
For a 6 inch pot, apply 4 fl. oz. of water for applications to the soil.
How often should a plant be watered?
“So a plant that’s in a 20-inch pot may only need water once every three to four weeks, whereas that same exact plan in a six-inch pot, might need water every one to two weeks. So that’s where the size of your plant and how much soil comes into play.” How much water should you give a plant a week?