Plant care guide: internal and external plants

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Plant care alerts 101

(i) If your space has a full-service maintenance contract from Underleaf, we will take care of the essential plant care and upkeep for you under the terms stated in your maintenance contract. 

(ii)If your maintenance visits are less frequent, or you have opted to take on the (very rewarding) care of your own plants, please find a detailed summary of the care guidance essential for long-term success.

Key things to be aware of...

  • Drooping / wilting leaves

    - Can indicate the plant is receiving TOO LITTLE water: check the substrate 
    - Can indicate the plant is receiving TOO MUCH water: check the substrate
  • Browning and dried-out leaves

    - Usually indicates that the plant is not getting enough water over a long period of time (a stress-indicator)
  • Fading colour

    - Can indicate a lack of nutrients or a response to pest damage. Check the leaves and stems. Check the substrate moisture-level
The above can also be a sign of overwatering: again, the importance of checking the substrate frequently cannot be overstated

Other watch-outs...

- Plants in small pots are more likely to require watering more frequently 
- Watering must be done slowly and repeatedly until ALL parts of the substrate is soaked
- Check plants for vandalism: if they have been pulled from the soil and left elevated, they will need to be re-planted properly to avoid them drying out 
- Make sure you check all plants, especially any smaller examples that are hidden behind larger companions, for they can be easily missed.
Make sure plants are not positioned close to, or moved to locations in front of heaters or air-conditioning units

(i) Watering: internal plants

Best practice

(i) CHECK: once per week 
(ii) WATER: once per week (NOTE: this is dependent on (i) checking: they may not always require additional water, but it is vital to check)
- Interior plants will need to be watered approximately once a week, depending on the plant and its location 
- Some plants are more ‘thirsty’ than others: seasonal changes such as increased Summer light levels and warmer temperatures will affect a plant’s use of its resources (For e.g higher light / warmth = higher demand for water) 
- Plants closer to windows and heat-sources are likely to require more water 

How to check?

- Put your finger into the soil before watering to see if it is moist (push your finger a good 1-2 cm into the surface of the substrate) 
- The soil at 2 cm beneath surface and lower should never feel completely dry, nor feel claggy
- It should ideally be a slightly darker colour and slightly moist to the touch. If you find the soil feels as if you’ve watered it very recently, leave it another few days to dry out before you water again. Succulent varieties of plant do not need as much water and should be allowed to dry out between waterings
Plants need to be checked frequently, and watered regularly: ie once a week, and thoroughly, so that the water filters all the way down to the deepest roots.
However, it is also very important not to overwater plants, especially those in planters and containers that are built-in troughs. If plants are overwatered, the excess will not be able to drain away, sitting in the base of the container and cause the roots to rot.
Watering instructions

- Use a watering-can or container with a sensible volume. 
- Water the top of the soil, aiming the spout of the can directly into the ‘heart’ of the plant to ensure that the water reaches deeply into the root mass 
- Roots occupy the lower parts of the pot: ensure that you water deeply and generously enough to reach this layer 
- Do not leave your plants sitting in excess water 

How much?

The exact amount of water needed will depend on the size of your plant and the container, and will vary depending on the time of year (more in the summer, less in the winter). 

“It is important you check the soil throughout the year as a plant’s watering needs will vary as the seasons change. Typically, the higher light levels and warmer temperatures in Spring and Summer will mean that an interior plant will be growing quickly and using resources more rapidly. In the cooler, lower-light of Autumn and Winter, your plants may need correspondingly less water and nutrition” 

Some useful notes on plant categories

(i) Tropical Plants 
Plants from tropical, forest environments need more moisture and humidity, so they’re more likely to suffer if you put them next to a radiator for example. And most importantly, tropical plants require consistent watering in order to keep their compost moist (but not wet!) we recommend to check weekly (like we said, get your hands dirty…stick a finger into the pot) and if the top 1-2cm of the substrate feels dry, then it’s time for a drink. 
(ii) Succulents (note, all cacti are succulents!) 
Succulents tend to need more light, and less water, preferring to dry out between each watering. Allow the compost to dry thoroughly between each watering, and never leave the plant sitting in excess water.Check the soil before watering again (the top 2-3 cm will tell you when to repeat)

Plants in a lined pot

All of our large planters contain waterproof liners. By following the rule of checking with a finger (get your hands dirty) you will easily be able to judge if the plant needs a drink. Overwatering plants in a large, lined container can mean having to uproot them to rid the soil of surplus water that is collecting in the base of your liner or pot. As ever, feel the soil a few centimetres below the surface and only water if it feels slightly dry.

(ii) Watering: external plants

Best practice

(i) CHECK: once per week 
(ii) WATER: once per week (NOTE: this is dependent on (i) checking: they may not always require additional water, but it is vital to check)
- In Summer, we recommend that plants are watered thoroughly three times per week 
- It will depend on size but, an average trough should receive at least 10l of water
- If it is especially hot, or windy, or both, they will benefit from more water more frequently 
- Substrate should not be completely dry to the touch or appear very light brown in colour (i.e ‘dusty’) 
- Soil should not feel ‘claggy’ or wet/ sticky. If it does, the plant does NOT require further watering 
- A dry plant will feel light in weight, and once watered should be considerably heavier - In colder months, watering can take place once per week 
- In Winter, plants do still use resources and will still need to be checked regularly to ensure that they do not dry out
Plants need to be checked frequently, particularly in hot or windy weather when they dry out faster. Most plants should be watered when the soil starts to feel dry to the touch. Water generously and thoroughly so that the water filters all the way down to the deepest layers of the planter, all areas of the root system need to be evenly irrigated.
Plants prefer to be watered thoroughly, less often, rather than a little drop everyday. A deep, thorough soak will penetrate the entire substrate and reach all the plants roots, which a light sprinkle will not.
Dealing with extreme dry soil 

It happens: sometimes a plant can become forgotten about, or left dry for longer than ideal. Here’s a fast way to take quick action and tackle an overly-dry plant. 

Signs of a dry plant

- Wilted, dry leaves and stems 
- Pale, caked soil that is dust-dry to the touch 
- Soil which has ‘shrunk’ and come away from the perimeter of the container 

If the soil is so dry that most of the water runs off, or runs straight through the drainage holes, you need to open up the soil. The best way do this is as follows: 

Step 1 
Plunge the whole pot into a bucket of water. If your pot has a waterproof liner, fill it up with water until it’s about 3/4 full and let the plant sit for about 30 minutes. 
Step 2 
After 30 minutes, lift the plant out of the liner and let all surplus water drain away. 
Step 3 
Wait another 30 minutes, lift the plant out of its nursery pot and check the soil profile. You should see the moisture evenly distributed through all layers of the soil. If this is not the case and there are still some dry layers visible, repeat the process.


Light levels

It’s important that plants have adequate light to survive and flourish. It provides energy that plants need to convert water (taken in through the roots) and carbon dioxide (absorbed by the leaves) into carbohydrates that make up the structure of a plant. 

The following pages detail the definition of light levels: from ‘Shade’ to ‘Direct’. These terms are often challenging to quantify or give 100% definitive guidance on. 

Our eyes perceive brightness in a way that is often at odds with what a plant actually demands for its survival. Just because we can ‘see’ adequately in a shaded corner, that’s not to say our photosynthesising companions will thrive here. The

Light levels in low light months

During low light months (November to March), the best place for plants is in front of a window. Many plants can suffer and react quite dramatically with by shedding their leaves when placed in low light conditions. During this time of the year make sure you position your plants in the sunniest location possible, at least temporarily, until the days are longer and the light intensity of the sun is stronger. definitions, and the individual plant-care instructions, will guide you on the optimum position for your plants.


Well away from a window, but enough light to read a newspaper during most of the day. Few foliage plants will completely relish these areas. Some exceptions could include Aglaonema, Aspidistra and Asplenium (ferns) Many Semi-Shade plants can adapt to survive here but their growth may slow noticeably.


Moderately-lit area within 2-2.5 metres of a sunny window (South-facing) or very close (within 1.5 metres) to a sunless window (North-facing) Many tropical foliage house plants will grow happily here. Most of the ‘Bright, but Indirect Sun’ plants will also adapt to this location.

Bright / indirect

Area close to, but not in the zone illuminated by direct sunlight (intense midday sun) Most plants will enjoy this location best: a region which extends approximately 1.5- 2.5m around a window which is sunlit for part of the day.
Some Direct Sun
Brightly-lit area, with some direct sunlight reaching the leaves during the day. A good example would be on an East or West-facing windowsill, or a space approximately 1m away from a South-facing window. Many plants will thrive in this zone: be aware that some delicate leaves can burn or scorch, however.
A zone with as much light as possible. On, or very close to, a South-facing window. Ideal for cacti, succulents and plants from arid or desert climates. Most forest or under-story plants will find this zone too intense and their leaves will scorch.

General care and grooming

General grooming 

Every so often, pick-off any dead leaves and gently wipe the healthy leaves to remove any dust and accumulated grime, as dirty leaves can greatly reduce the plant’s ability to absorb light. A gentle wipe with a clean, soft cloth will not only improve the look of your plant, but will greatly help it to thrive and grow. 


It is beneficial to dust the leaves of larger plants every two weeks Again, assign this task to a rota’d member of staff so that your plants will remain reliably and consistently presentable and in the best of health.
Plants that are covered in dust will not be able to photosynthesize properly
- Use a clean damp cloth, idealy dedicated only to plant care only
- Wash the cloth frequently while dusting
- Use a clean cloth for each plant to prevent the transfer of pests and diseases
- Small plants can be carefully washed in the sink with cool to lukewarm water (never hot) and left to drain before being returned to their usual location


Throughout the spring and summer months (April to October) your plants will like to be fed. Generally the most accessible and convenient form of plant fertiliser comes as a liquid-soluble, that can be added to your plants water. 

Always follow the instructions on the bottle and don’t exceed the recommended concentration. For more specific advice, or if you have followed the steps above and your plant is still not doing well, get in touch with us and we will be happy to guide you in fertiliser selection and application.

People often ask how soon will I need to move my plant into a bigger pot? 

As always, it’s difficult to give hard and fast rules. Generally, the smaller the pot, the sooner you’ll need to size up. Again, succulents and tropical plants tend to behave differently, succulents will be happy in the same pot for a lot longer than most other faster-growing and nutrient-hungry tropical plants. 

Here are some key signs it's time to size up

- If roots are escaping from the bottom of the pot it’s usually a clear sign that your plant is pot bound and could do with more room
- You find the soil in the pot has caked together, and rather than absorb water it simply runs straight through and down the sides. This is another indication that the current compost is tired and compacted, and should be replenished. 
- If your plant is getting top heavy and looks too big for its pot, don’t beat around the bush, treat it to a bigger one

When stepping-up to the next size, your plant will usually only need a pot with an additional 4-6 centimetres in diameter. However, if you’re dealing with a large plant, it makes sense to give it extra room, as it will expand into its new space more quickly, and it’s likely that you won’t want to pot on again for a while. It's worth noting again that the most common maintenance error is over-watering...and the fastest way to kill your plant. When plant roots have to deal with excess water they can rot quickly, and this essentially removes the plants ability to access nutrients and, ironically, the water it needs. Therefore, drainage is key. Getting the watering and drainage right for each plant is essential for long-term success. See our ‘Planter setup’ below for further info.

Planter setup

Traditional terracotta plant pots (and the plastic nursery pot in which your plant is grown in) will have ample drainage holes to allow the escape of excess water. This pot can be placed on a saucer to collect the run-off however, we do not to rely on this method as it's not fool proof arguably less visually pleasing. 

Typically, decorative pots and planters do not have drainage holes. They look great with your plant in them but, how do you ensure your precious plants can drain properly when watered? We use a waterproof liner, drainage layer and decorative topping. This not only looks great, but ensures the safety of your furnishings too. 

Here’s how we do it: