The science behind how much light and water your plants need.
Russell Page very rightly said “If you wish to make anything grow, you must understand it, and understand it in a very real sense. 'Green fingers' are a fact, and a mystery only to the unpractised. But green fingers are the extensions of a verdant heart.”
While gardening with your own two hands and watching plants grow is a joy like no other, no gardening journey is without its losses. But the idea is to always strive for lesser casualties and more joy. I have personally seen people struggle with getting the light and water right for some plants and we get many customers who are not very sure about what is bright indirect or medium light. So here we are, with a detailed scientific approach for plant survival.
While we can wax eloquent about gardening for days, this blog has to be on point to deliver as much useful knowledge in as little time as possible. With this piece, we aim to tell you about what role water and light play in plant growth, understanding various types of light, understanding soil types and water retention. We will also talk about the watering needs of different types of plants and the ever elusive but easy to grasp concept of ratio of light to water.
So let’s get started!
What is photosynthesis?
We have all studied it but let’s revisit it from a gardening perspective, the process of photosynthesis. It is the process by which plants use light to convert water, carbon di-oxide, and nutrients in the soil to energy rich organic compounds for their growth. So it is essential that plants get the right ratio of light to water and are planted in a pot that is right for their size. It is also essential to understand that potted plants do not have an unlimited source of nutrients, as the soil remains the same for years, so replenishing the nutrients by external means is absolute for a healthy growth.
It’s not just sunlight and artificial light! There are several other terms in the entire spectrum, like bright direct, dappled shade or sun, bright indirect, medium indirect, and low light. Lets tackle them one by one:
- Bright direct light: This is the easy one, it is direct sunlight. The one that makes us pull out or caps and shades and put on sunscreen is what we garden gnomes call bright direct light. It can be the morning sun or the blazing afternoon. The idea that even plants that love the sun die in the hot afternoon is a myth that we shall tackle in the later sections.
- Dappled shade/sun: Imagine standing under the shade of a tree and small beams of filtered sunlight reaching you – that is dappled sun/shade. This can be achieved in home with the green sun-shade you can buy from Amazon or any hardware shop by yardage at a nominal price. This is especially handy for people with south facing terraces whose plants burn out in peak summer.
- Bright Indirect: The light spectrum where the plants are in a party mood! Loved by almost all plants, or rather all. What exactly would you call bright indirect? Natural light in which you can read a newspaper easily is bright indirect. Not a book, not your phone but the bleeding small font of a newspaper without angling the paper right or squinting.
- Medium indirect: Light that reaches your plant through sheer curtains or when the plant is placed at least 7-8 feet away from a bright window. You probably can’t read a newspaper but a book is fair game in this light.
- Low light: Low light is when no direct light reaches your plant whatsoever. Where you can probably read but also fall asleep in peace. It is the cool ambience in summer afternoons that puts you to sleep.
Understanding soil and water retention
There is more than just brown soil. Some are heavy dense, while others are lighter and loose. I have heard many people argue with me that nature perseveres despite circumstances and grows in whatever is available, even a crack in the concrete. While I am the biggest supporter of that statement, what we need to understand that growing certain plants for ornamental purposes and letting nature take over the land are two different things, similar to fishes in the lake and in an aquarium. In potted plants its essential to provide the right soil mix for both the plant’s benefit and your ease of gardening. A very dense clayey soil will hold too much water and might lead to root rot and also make it difficult for you to get the plant out of the pot at the time of repotting.
One of the most fail proof and generic soil mix is 2 parts garden soil, 1 part cocopeat, and 1 part compost. It has enough strength to provide the roots with a holding support, while the cocopeat help in aeration of the roots and the organic manure provides all the nutrients a plant requires for healthy growth. The cocopeat also comes in handy when the plant has to be removed and repotted in a bigger pot.
The philosophy of “moist but not soggy” soil is all about having the right type of soil that does not turn into muck and drown the roots on watering, rather retains the right amount of moisture and lets the excess drain out.
Understanding the watering needs of different kinds of plants
Different plants photosynthesise at different speeds and it all depends on where they come from. Tropical plants like ferns that grow on the forest floor love indirect light with lots of humidity, mimicking the conditions they grow in. Whereas palms and succulents worship the sun in their dry as the desert potting medium. It is important to know your plants and where they come from, treat them as individuals with varying needs and you will realise they are not so different after all.
Water your ferns more regularly and palms just as rarely. If you have plants with bulbous roots (ZZ) or fleshy leaves (crassula) then let them be for a while, they store enough water to live freely. Thick but non woody tropical plants like the aglaonema are good with infrequent watering but love humidity. Plants with woody stems are more drought tolerant, meaning they prefer being underwatered than overwatered any day.
Understanding the water to light ratio for plants
Remember this, when a plant gets more light (brighter or for a greater number of hours) it will need more water and when it gets lesser light it will require comparatively lesser water. Water is a direct requirement of photosynthesis and evaporation of moisture from the leaf surface, so more sunlight means more requirement for water. So in those hot summer months when you feel that your plants are drying out far too much, all they need is, to be watered twice a day.
PS: Ensure that the foliage is dry when watering in peak sun, the little water droplets work as a magnifying glass for sunrays and lead to leaf scorching.
The mantra is pretty simple, more light means more water but only when your plant needs it. Don’t water your succulents daily just because they are in the sun, also don’t stop watering your ferns just because they are indoors because they love water. Understand you plants and where they come from. Look for signs like yellowing leaves that is a sign of overwatering, while browning tips are a sign of underwatering or infrequent watering.
Gardening is easy, take a breath and look at your plants, really look at them. Treat them as living beings with needs and signs of both distress and happiness. The occasional dry leave are natural and a part of the natural progression. In any case if you are a part of the Ugaoo family and you have issues that are beyond your understanding, then give us a call and let us help you in your gardening journey.