5 - Watering, part I: H2O and the plant. Frequency of watering
If your plants suffer shortage of light for a while, they will tolerate it. But water deprivation will kill them. As we know, water is essential for germination and growth. And as usual, every type of plant, and every stage of growth, shows different needs; cacti and succulents store moisture within their tissues and are able to manage well in case of drought, but leafy seedlings have no reserves and the time between getting slightly dry and dying goes by very fast.
Each plant has different tolerance to wilting and has different ranges for recovery. Partial wilting, while better avoided, is not fatal; the little brown ends in leafs, well known by salvia or chacruna gardeners, are a result of localized partial wilting, and they are not a disaster – but they should be a warning sign, as long as you understand that language.
So, once again, the gardener's homework includes this as a key assignment: Know Thy Plant. Being aware of the particular needs of the plant you want to grow, and understanding some principles about watering, is all you need to be able to keep your plants well greased.
5.1. – H2O and the plant
Plants use water to:
- Feed and regulate the metabolism of the plant.
- Transport around the soluble sugars produced in photosynthesis and the mineral ions fished by the roots.
- Maintain plant structure, keeping the plant turgid and able to support its own weight.
- Protect the plant against wide temperature fluctuations, thanks to water transpiration in the leaves.
Water is also essential to dissolve the mineral nutrients available in the substrate, so the roots can capture them by osmotic exchange.
Besides the digestion of water in the chloroplasts, the little photosynthetic machines that break down H2O using the energy of light, there's two other water-related components in plant anatomy that you should meet.
Stomata (singular: stoma) are tiny pores generally concentrated on the underside of the leaves, out of direct sunlight. They are the responsible for the gas exchange in plants, acquiring carbon dioxide from the air and releasing oxygen as a byproduct of photosynthesis. (In a side note, the output oxygen is larger than the input of CO2, which explains the air purifying effect of the plants and the fact that all animal oxygen-breathing life in the planet owes them at least a fist bump.)
Normally, stomata open when the light strikes the leaf and triggers the whole photosynthetic process, and they close at night time. Stomata also perform an important role in the immune system of the plant, reacting to the intrusion of bacterial compounds - not unlike what happens in the mouths and other openings in animals. The lips of stomata, called guard cells, modify their structure when exposed to blue light thanks to a change in osmotic pressure.
It's no wonder that the highest levels of osmotic pressure, and hence the widest opening in stomata, occur at noon in plants growing outdoors, when the sunlight energy is at its peak. High carbon dioxide concentration and high humidity also favor the opening of stomata.
Another key process they allow is the evaporation of water towards the atmosphere, called transpiration. This is the plants way of sweating, and although it occurs as a side effect of having their mouths open allowing the water vapor out, transpiration carries out essential functions for the plant: It helps to regulate the temperature in the plant surface, and by changing the hydrostatic pressure in the plant tissues, also pumps up water and minerals from the roots in another chapter of osmotic exchange. Which is to say, when the feeder roots sense water shortage in the soil, stomata will close to keep the precious water available. This defense system has a limited efficacy, though; the water shortage will eventually make the plant suffer and might be fatal.
Stomata are formed during the initial stages of plant development, and therefore they reflect the environmental conditions under which they grew. For instance, plants of the same species growing in different levels of ambient humidity will show different density of stomata. A sturdier plant used to drier environment will develop less stomata as a way to decrease the loss of water by transpiration; that, of course, decreases the photosynthesis rate, making the plant grow slower when compared to another individual in a more humid environment.
Vacuoles are cell components (organelles) that are shared by most plants, animals and fungi. They are multifunctional, although generally serve as storage compartment. Most plant cells have one large vacuole that can occupy from 30% to as much as 90% of the cell's volume.
In ideal conditions, they are basically full with water, which sustains the shape of the cell (hence the structure of the plant tissue) and allows storage of minerals, proteins, enzymes, and waste products. They are also responsible for the straight structure of the plant thanks to hydrostatic pressure.
Many of the valuable tryptamines you have extracted have been patiently stored inside of the plants vacuoles until you eagerly broke their walls with physical and chemical alterations.
5.2.– Frequency of watering
There's two ways your plants will lose water: evaporation from the substrate, and transpiration from the leaves. Other than that, water is indefinitely recycled, exactly as in the larger scale of things.
You should water more or less often depending on several circumstances:
a) Age and Growing stage. Young plants need frequent, light watering since they do not have yet the resources to make up for water shortage. Mature plants that are in a quick growing period will make good use of frequent watering too. Whenever you are reproducing or following seasons, plants that are coming out of the rest period often associated to winter (when water requirements drop significantly) will appreciate having more water available. So if you have a spring in your indoor, more water will be welcome. A known extreme example of this can be found in lots of cacti and succulents, that will do fine with barely any water during their winter rest season and will subsequently welcome early spring water.
b) Ambient humidity. For the aforementioned reasons, a high ambient humidity will decrease transpiration (and increase capture of water by the leaves) and lower the amount of evaporation from the soil, which decreases the frequency of watering.
c) Temperature. Heat increases transpiration, as you know. We drink more in summer too.
d) Air flow. If the air under the leaves moves more frequently, it will nicely refresh the CO2 available but also blow the water vapor away, so the plant will replace it more often. So using abundant ventilation also raises the need for water. However, we must assume that any specific watering guidelines for a plant presume ventilation, so the practical consequence of this goes the other way: plants with reduced air flow, or isolated from air flow, require less watering.
e) Flowering and fruiting periods, where most plants will need some extra water.
f) Repotting times. Generally, if the plant is pot bound and has to be repotted soon, it will need more water than if it has been just repotted. The reasons for this are several. First, the growing substrate in a pot full of roots holds water worse and drains faster. And second, the plant and its root system will be bigger than ever before in that moment. When we have just repotted a plant, and once we have made sure that the new substrate is moist enough, we don't want the roots to be lazy; we want them to get to work and dig deeper looking for water, and a little less frequent watering (while making sure that the other needs, specially light and air, are well covered) will help the plant grow downwards rather than upwards. And that's the first requirement for her to be able to grow upwards as we want her to do.
The most important of them all, though, is the particular needs of every type of plant. You are highly encouraged to learn about the documented water requirements of the species you are growing. Plants might require a substrate slightly dry, moist, or thoroughly moist, and that will determine whether you have to check/water them weekly, every three or four days or every other day. If you cannot find specific information about your plant's water needs, learn about the natural conditions the plant grows in and do your best to reproduce them. Until you get well acquainted with your plant, it's a good idea to check on it often.
To sum this up:
- You should water the plants more often if they are seedlings, if it's hot, if it's dry, if it's growth (spring-summer) season, if they're flowering, if they are under abundant ventilation or if they are root bound.
- You should water your plants less often if they are in a rest period, if it's very humid, if it's cold, if there's poor ventilation or if they were just repotted.
Other than that, you should water them follow the average needs for the species you are growing.
In any case, a continuous wet substrate is generally to be avoided. We don't want the roots to drown or to rot. For most plants, it's better to water regularly than drowning them after a period of drought. So good balance is the key. Keep in mind, though, that very frequent and shallow waterings are generally not beneficial. Doing that promotes root growth closer to the surface, where roots are more vulnerable to drying out. We want to promote roots digging deep instead, so go for thorough, well drained watering every X days, as needed.
As for the best time to water the plants within the day period, you should water the plants if possible in the beginning of the light/day time. This way you give the plant the whole day to use the water, and lose less water to evaporation. Also, watering in the evening serves better the interests of fungi that thrive better under dark and moist conditions.
Now that we've discussed why and when, in the next post I'll talk a little about which water to use and how to deliver it. We already know about the who. In this case it's you instead of the rain.
Thanks for reading![Smile :) :)](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
If your plants suffer shortage of light for a while, they will tolerate it. But water deprivation will kill them. As we know, water is essential for germination and growth. And as usual, every type of plant, and every stage of growth, shows different needs; cacti and succulents store moisture within their tissues and are able to manage well in case of drought, but leafy seedlings have no reserves and the time between getting slightly dry and dying goes by very fast.
Each plant has different tolerance to wilting and has different ranges for recovery. Partial wilting, while better avoided, is not fatal; the little brown ends in leafs, well known by salvia or chacruna gardeners, are a result of localized partial wilting, and they are not a disaster – but they should be a warning sign, as long as you understand that language.
So, once again, the gardener's homework includes this as a key assignment: Know Thy Plant. Being aware of the particular needs of the plant you want to grow, and understanding some principles about watering, is all you need to be able to keep your plants well greased.
5.1. – H2O and the plant
Plants use water to:
- Feed and regulate the metabolism of the plant.
- Transport around the soluble sugars produced in photosynthesis and the mineral ions fished by the roots.
- Maintain plant structure, keeping the plant turgid and able to support its own weight.
- Protect the plant against wide temperature fluctuations, thanks to water transpiration in the leaves.
Water is also essential to dissolve the mineral nutrients available in the substrate, so the roots can capture them by osmotic exchange.
Besides the digestion of water in the chloroplasts, the little photosynthetic machines that break down H2O using the energy of light, there's two other water-related components in plant anatomy that you should meet.
Stomata (singular: stoma) are tiny pores generally concentrated on the underside of the leaves, out of direct sunlight. They are the responsible for the gas exchange in plants, acquiring carbon dioxide from the air and releasing oxygen as a byproduct of photosynthesis. (In a side note, the output oxygen is larger than the input of CO2, which explains the air purifying effect of the plants and the fact that all animal oxygen-breathing life in the planet owes them at least a fist bump.)
Normally, stomata open when the light strikes the leaf and triggers the whole photosynthetic process, and they close at night time. Stomata also perform an important role in the immune system of the plant, reacting to the intrusion of bacterial compounds - not unlike what happens in the mouths and other openings in animals. The lips of stomata, called guard cells, modify their structure when exposed to blue light thanks to a change in osmotic pressure.
![Stomata.jpg](/proxy.php?image=http%3A%2F%2Fap-bio-chs-plants.wikispaces.com%2Ffile%2Fview%2FStomata.jpg%2F140645275%2F652x357%2FStomata.jpg&hash=dc7c0a4170d11051e6b6fb9da1494c86)
It's no wonder that the highest levels of osmotic pressure, and hence the widest opening in stomata, occur at noon in plants growing outdoors, when the sunlight energy is at its peak. High carbon dioxide concentration and high humidity also favor the opening of stomata.
Another key process they allow is the evaporation of water towards the atmosphere, called transpiration. This is the plants way of sweating, and although it occurs as a side effect of having their mouths open allowing the water vapor out, transpiration carries out essential functions for the plant: It helps to regulate the temperature in the plant surface, and by changing the hydrostatic pressure in the plant tissues, also pumps up water and minerals from the roots in another chapter of osmotic exchange. Which is to say, when the feeder roots sense water shortage in the soil, stomata will close to keep the precious water available. This defense system has a limited efficacy, though; the water shortage will eventually make the plant suffer and might be fatal.
Stomata are formed during the initial stages of plant development, and therefore they reflect the environmental conditions under which they grew. For instance, plants of the same species growing in different levels of ambient humidity will show different density of stomata. A sturdier plant used to drier environment will develop less stomata as a way to decrease the loss of water by transpiration; that, of course, decreases the photosynthesis rate, making the plant grow slower when compared to another individual in a more humid environment.
Vacuoles are cell components (organelles) that are shared by most plants, animals and fungi. They are multifunctional, although generally serve as storage compartment. Most plant cells have one large vacuole that can occupy from 30% to as much as 90% of the cell's volume.
In ideal conditions, they are basically full with water, which sustains the shape of the cell (hence the structure of the plant tissue) and allows storage of minerals, proteins, enzymes, and waste products. They are also responsible for the straight structure of the plant thanks to hydrostatic pressure.
![vacuole.jpg](/proxy.php?image=http%3A%2F%2Fmiddletownhighschool.wikispaces.com%2Ffile%2Fview%2Fvacuole.jpg%2F98890673%2F454x555%2Fvacuole.jpg&hash=dd0cc0b52af759fbc34c6c654092a5b8)
Many of the valuable tryptamines you have extracted have been patiently stored inside of the plants vacuoles until you eagerly broke their walls with physical and chemical alterations.
5.2.– Frequency of watering
There's two ways your plants will lose water: evaporation from the substrate, and transpiration from the leaves. Other than that, water is indefinitely recycled, exactly as in the larger scale of things.
You should water more or less often depending on several circumstances:
a) Age and Growing stage. Young plants need frequent, light watering since they do not have yet the resources to make up for water shortage. Mature plants that are in a quick growing period will make good use of frequent watering too. Whenever you are reproducing or following seasons, plants that are coming out of the rest period often associated to winter (when water requirements drop significantly) will appreciate having more water available. So if you have a spring in your indoor, more water will be welcome. A known extreme example of this can be found in lots of cacti and succulents, that will do fine with barely any water during their winter rest season and will subsequently welcome early spring water.
b) Ambient humidity. For the aforementioned reasons, a high ambient humidity will decrease transpiration (and increase capture of water by the leaves) and lower the amount of evaporation from the soil, which decreases the frequency of watering.
c) Temperature. Heat increases transpiration, as you know. We drink more in summer too.
d) Air flow. If the air under the leaves moves more frequently, it will nicely refresh the CO2 available but also blow the water vapor away, so the plant will replace it more often. So using abundant ventilation also raises the need for water. However, we must assume that any specific watering guidelines for a plant presume ventilation, so the practical consequence of this goes the other way: plants with reduced air flow, or isolated from air flow, require less watering.
e) Flowering and fruiting periods, where most plants will need some extra water.
f) Repotting times. Generally, if the plant is pot bound and has to be repotted soon, it will need more water than if it has been just repotted. The reasons for this are several. First, the growing substrate in a pot full of roots holds water worse and drains faster. And second, the plant and its root system will be bigger than ever before in that moment. When we have just repotted a plant, and once we have made sure that the new substrate is moist enough, we don't want the roots to be lazy; we want them to get to work and dig deeper looking for water, and a little less frequent watering (while making sure that the other needs, specially light and air, are well covered) will help the plant grow downwards rather than upwards. And that's the first requirement for her to be able to grow upwards as we want her to do.
The most important of them all, though, is the particular needs of every type of plant. You are highly encouraged to learn about the documented water requirements of the species you are growing. Plants might require a substrate slightly dry, moist, or thoroughly moist, and that will determine whether you have to check/water them weekly, every three or four days or every other day. If you cannot find specific information about your plant's water needs, learn about the natural conditions the plant grows in and do your best to reproduce them. Until you get well acquainted with your plant, it's a good idea to check on it often.
To sum this up:
- You should water the plants more often if they are seedlings, if it's hot, if it's dry, if it's growth (spring-summer) season, if they're flowering, if they are under abundant ventilation or if they are root bound.
- You should water your plants less often if they are in a rest period, if it's very humid, if it's cold, if there's poor ventilation or if they were just repotted.
Other than that, you should water them follow the average needs for the species you are growing.
In any case, a continuous wet substrate is generally to be avoided. We don't want the roots to drown or to rot. For most plants, it's better to water regularly than drowning them after a period of drought. So good balance is the key. Keep in mind, though, that very frequent and shallow waterings are generally not beneficial. Doing that promotes root growth closer to the surface, where roots are more vulnerable to drying out. We want to promote roots digging deep instead, so go for thorough, well drained watering every X days, as needed.
As for the best time to water the plants within the day period, you should water the plants if possible in the beginning of the light/day time. This way you give the plant the whole day to use the water, and lose less water to evaporation. Also, watering in the evening serves better the interests of fungi that thrive better under dark and moist conditions.
Now that we've discussed why and when, in the next post I'll talk a little about which water to use and how to deliver it. We already know about the who. In this case it's you instead of the rain.
Thanks for reading