If you are blessed with a natural green thumb, then continue doing what you’re doing. But if you’re like the rest of us mere humans, it takes time and a lot of trial and error to figure things out. It’s important to know some indoor gardening basics to give you the best chance to grow gorgeous plants.
Understand what goes on above and below the dirt and you will save yourself some of the hassles. You might want to revisit that issue after killing a lot of your plants, but why not get all of your basic questions answered upfront with an indoor gardening guide?
We’ll take a closer look at how edible plants grow, then give you some actionable tips on what you need to do to propagate them healthy even as a beginner. Gardening indoors can be learned by anyone!
How Does A Plant Grow?
Most likely your plant will be bought in the store or acquired from someone already fully grown. We will discuss in more detail how to mature plants later, but let us begin at the very beginning – the seeds themselves.
It is a wonderful process to grow a plant from seed, and with some indoor gardening tips, you can do it too.
Plant Growth Stages
All plants go through stages of development. We usually don’t think about them that much. Plants grow just as quickly as a seed is planted in a pot, but they require different needs at different stages in the development process.
One small shell contains all of the beginnings of the plant, as well as what it needs to grow and grow until it can form a root. A seed is made up of the seed coat, the endosperm, and the embryo.
Upon first glance, we can see only the seed coat. This thick exterior serves as protection for the very young plant. From there, the endosperm provides all of the nutrients a plant initially needs. The endosperm surrounds the embryo in most seeds, providing it with a readily accessible source of nourishment. The endosperm is not just for plants — everyone who’s had popcorn or white rice has eaten delicious endosperms.
A plant embryo is composed of three major components: roots, cotyledons, and embryonic leaves. All of these are tucked inside that tiny little seed.
Our knowledge of plant roots is well known. However, cotyledons are external food sources for individual plants once they emerge, and embryonic leaves are the first two leaves to appear once the seed germinates.
So long as you store your seeds properly, they’ll stay viable for years. Seeds should be stored in an air-tight container if they’ll be in moisture, but the endosperm will slow germination as time goes by.
A seed is said to have germinated when it emerges from its shell. A seed must germinate under two conditions:
- Water. Upon soaking up water, seeds rehydrate. This triggers the growth process.
- Warmth. The seed needs to be at a constant temperature to germinate properly, and if it’s too cold or too hot, it will remain dormant.
Some vegetables can take a few days to sprout while others can take weeks. Here is what can delay germination:
- The seeds are planted too deeply. Please follow the seed instructions for each kind of seed. Some seeds can be placed above the soil’s surface while others prefer being under the soil’s surface.
- Bad quality seeds. Make sure seeds are tested for germination rates before they are sold to make sure they aren’t selling duds. Use organic and non-GMO seed suppliers to ensure quality. Test a small handful of leftover seeds from the previous season to see if they germinate well. If so, go for it.
- Too little or too much water. Usually, seeds need to sprout in evenly moisturized soil. If it is dry, they will not sprout. If it is too wet, the seedling can drown!
Seeds survive on their endosperm as they germinate. They send out their roots to establish a support system that will allow them to draw mineral nutrients from the soil to grow further.
Since the seedlings’ roots have grown downward recently, they need to start spreading their leaves outward so they can start producing the energy they need from adequate light.
In the vegetative stage of development, plants expand the area of their stem, branch, and leaf so they can reach light areas. They grow more leaves and bigger leaves at this time so they can absorb more natural light.
They’re also hungry for nitrogen (on the N-P-K fertilizer labels, the N stands for nitrogen). This nitrogen is what allows plants to obtain energy from light by producing chlorophyll.
During the reproductive phase, the energy used for plant growth will now go toward flowering or fruit growth. During reproduction, phosphorus helps assist with flowering and fruit growth.
Plants react to changes in the length of daylight by changing their photoperiod, which itself is known as photoperiodism. However, plants just notice the light itself, regardless of where it came from. This is why artificial lighting can be used to control plant growth indoors. Your plant will grow as long as the light is similar to natural sunlight.
This stage also includes the pollination of plants, which helps to protect seeds and promote reproduction. If your indoor garden requires pollination, then you are responsible for carrying out the process.
People brush a cotton swab gently against the interior of the flower and then continue to the next flower and the next. It’s not a complicated procedure, and not necessary on non-fruiting plants or plants for which nothing will be gotten from the seeds.
Many perennial gardeners are familiar with dormancy, a stage of life that is often ignored by annual plant growers. Dormancy is a good thing to know about since annual plants do not have it. This phase occurs when a plant suspends its growth until a more optimal environment is achieved.
During the winter months or summer heat, the trees appear to be dormant. The birds may seem to be dying during this period. It’s not like they don’t have the energy to waste, instead, they’re conserving some for a future time of need.
The hours of light decrease during the winter, which results in lower temperatures; dormancy also occurs in cold-loving plants during the summer, and the plant will emerge when the heat subsides.
It is not unusual for outdoor plants to go dormant during the winter months of December through February in the U.S. Thankfully for us, plants that go dormant in summer may thrive at room temperature in winter. Dormancy is the best time to withhold fertilizers and water less because the plants will not be taking up as much as they normally do. If you begin to lose water and nutrients when your plants decline, you shouldn’t assume they are in a dormant phase, so treat them normally.
By now you’re well-versed in stages of plant growth. Now let’s get to other key facts about how plants grow.
About The Roots
A tree or plant may be appreciated for what’s on the outside, but what’s on the inside is what makes the magic happen. Roots take up atmospheric and nutrient-rich air and water from the ground and carry it up to the leaves for photosynthesis, which in turn produces the energy in plants to grow.
The plant, tree, whatever it is, will reach a certain size if the roots don’t have adequate space to grow, and will be unable to grow any further. It’s the same as eating a certain number of calories each day to remain at the same weight. The body is unable to grow due to a lack of nutrition.
In contrast, if your plant displays good growth then suddenly begins to appear sickly, it may be a sign that your roots need more room to grow and the plant needs repotting. Conversely, people growing in an indoor setting can find it hard to grow their roots because they have too much space.
It is not the roots, but rather the excess soil that causes the problem. When watering a plant in a greater container than needed, the water becomes trapped in the soil, leaving the roots unable to absorb the moisture. This causes the roots to rot instead of expanding because of the reduced aeration of the soil. It doesn’t happen in nature because of the better drainage of the soil.
How do you handle damaged roots? The good news is that a plant’s roots can regrow when damaged. If the roots are damaged too deeply, the plant will wither. Without enough roots, it cannot obtain enough water, nutrients, and air.
The plant uses its leaves like solar panels to make use of light and thereby obtain energy from it. Technically speaking, photosynthesis makes glucose that is the fuel for the plant. However, I’m sure you remember this from school so we won’t need to broach that subject right?
Plants communicate incredibly well, but we are not very good at listening. How can we learn from observing the leaves? Here are a few ways to learn what plants need.
Water less often but still give your plants enough water. If you see your plants starting to turn yellow, stop watering them. You can find more information on plant nutrients here. If they continue to turn yellow, then they could be suffering from a nutrient deficiency and need some plant food.
If you see brown and crispy leaves on your plant, make sure the soil is damp and find the appropriate watering schedule. Don’t overwater them, but make sure it keeps dry enough without the leaves turning brown and crunchy.
Is your plant missing in action? It needs more water or sunlight! If there is insufficient water or sunlight, it cannot do photosynthesis, which leaves it unable to grow or develop. Try watering them more first. If that does not work, try getting them more light as well.
Do you see yellow spots on your plants? Pests can invade both indoor and outdoor plants. Yellow spots on your plant may indicate a problem with spider mites. Scales can also appear indoors and cause problems.
Things Plants Need To Grow
- Light. Plants can starve when they have low levels of light since they cannot produce food for themselves. Photosynthesis is the process by which plants turn to water, carbon dioxide, and nutrients into sugars they can eat.
- Water. Needed for photosynthesis and to enable the plant to extract nutrients from the ground. The water also provides moisture around the plants.
- Carbon Dioxide. Carbon dioxide is the primary component of air that plants breathe in to undergo photosynthesis.
- Medium for Growing. Plants usually need something to place their roots into to hold themselves upright and draw nutrients from their growing medium.
- Nutrients. All plants require different levels of nitrogen, potassium, and phosphorus to live, just like humans need nutritional supplements for good health. Plants also need these nutrients for a variety of reasons including assisting photosynthesis or growing a strong root system.
Let’s tackle some real-life tips once you’ve got your basics down.
Soil Plus Fertilizer
Soil is a living device that consists of nutrients, organic matter, water, air, earthworms, bacteria, fungi, and other living beings. Indoor plants need soil to draw upon the nutrients in them to live. Dirt is a “dead” matter that does not provide them nutrients.
How much soil should you buy? For indoor gardening, the best choice is organic potting soil rather than soil from your garden. This will prevent the spread of plant diseases and pests into your home or greenhouse.
How long will soil last? You can still use the soil decades down the line, but the nutrients will be depleted as microbes consume the soil. Check out the fertilizer section for tips on ensuring the soil has all the nutrients it needs.
The soil should be stored in an opaque container and kept in a stable, dry location like a garage or basement when it’s not in use. Keep your soil dry and clear of common garden pests. You don’t want it to get infected with bacteria or become infected with common garden pests. Check your soil every few months to make sure it’s in good shape and doesn’t grow spontaneously.
It is a concentrated source of nutrients meant to replenish the original nutrient content of the soil. To understand why this is important, read the section on how plants grow again.
Many forms of fertilizer exist: packaged types, worm poop, even your poop can be used as fertilizer. Basic fertilizers have a nitrogen, phosphorus, and potassium ratio in which each nutrient is essential for the growth of a plant. Different fertilizers can have different amounts of NPK for different types of plants.
The best choice of fertilizer depends on your plant but it would be best to get organic fertilizer. Synthetic fertilizers will degrade your soil quality over time, as opposed to organic fertilizers that will improve its quality. Use this guide to organic fertilizers to find the best one for you.
What should you do to apply fertilizer? Water your plants before you apply dry fertilizer so they are ready to consume the nutrients. Then follow the instructions exactly, depending on when the fertilizer is applied.
You should use 1/4 to 1/2 of the recommended dosage if you are using a packaged fertilizer that is not specifically formulated for indoor gardening since the amount of soil you have to fertilize is smaller. You can use liquid fertilizers when diluted to a strength suitable for houseplants (check the label) and substitute regular watering with them.
Do you need to flush your plants? Plants absorb nutrients from fertilizer, yet other parts may sit in the soil, which has adverse effects. Those who have drainage in their pots can consider heavily watering them and letting their pots fully drain every month. This will make sure the compost and fertilizer spread out and keep the soil healthy.
It doesn’t hurt to remind you that you need to water your plants; however, watering too much or too little can cause your plants to die, so let’s make sure you’re doing it right.
When should you water? Don’t worry about how much or when to water, pay attention to what the leaves can tell you. Check the soil as well. Is it still wet? Does it continue to look wet? Does it remain wet on top or if you stick your finger in the soil?
Water the plant only when necessary. Otherwise, the water will stagnate and may lead to mold. The roots of the plant still need air so if you put too much water in your container, the plant may drown.
You should water your plants differently depending on the plant type. Some plants will do better with watering from the bottom (because moisture will “wick” through the soil) while others will do better with watering from the top. It depends a lot on the variety, so research what works best for your plant. If you’re not sure, stick to the bottom, where the roots are the biggest.
If the number one cause of death for indoor plants is overwatering, drainage can be argued to be one of the best lifesavers. Drainage explains the effects of your watering mistakes. If possible, you should incorporate drainage. It’s okay to risk it sometimes, that’s why there’s a drainage hole. But, it would be much easier if you just have a drainage hole.
What should you do if there is no drainage? Be conservative with the watering you give your plants and keep a watchful eye on how long it takes for them to dry. Can you anticipate it dries within a few days? That should be OK for most houseplants. Watering less or improving airflow would be better alternatives for keeping the soil moist.
To reduce the risk of mold developing more rapidly in shorter time frames, you should dry the soil earlier than a few days before you grow vegetables or microgreens. If the plant is dying because of underwatering, then it can be brought back more easily than if it has died from overwatering.
You can’t talk about airflow without mentioning watering. Airflow and water are two of the main factors that contribute to mold and diseases in plants. Air circulation stimulates the evaporation of water and the prevention of mold when you grow your food inside.
It’s not necessary to always have direct air movement around your plants, but monitoring how quickly the soil dries up will help you figure out if they’ve got enough airflow. If your plants are not drying quickly enough, try increasing their airflow until you know if that is the best way to dry their soil.
Here are two ways you can improve airflow. Turn on the ceiling fan in the room every once in a while, or open a window if it’s warm enough. If you keep the plant near a window, the temperature will change throughout the day, thus creating a light “breeze” throughout the house. You can also take the plant outside during warmer months to provide it with improved airflow during the day.
A plant’s reproductive growth stage, when it is ready to produce flowers, fruits, or seeds, is influenced by light in addition to photosynthesis.
For most plants, you can influence growth by adjusting how much light they receive. This is especially crucial when they are a vegetable, such as lettuce, which goes from bitter to edible after flowering.
What kind of light does your plant need? Since this differs from plant to plant, search specifically for the amount of light that suits your plant. Plants generally fall into this range:
- Direct light: The sun needs to shine directly on some plants daily to grow strong. If they are indoor plants, then their only source of light is through a window.
- Indirect light: Direct light can be problematic for plants. The first situation is when a plant is sensitive to even small amounts of direct light, so indirect light is preferable. Secondly, if you do not have direct sunlight available for the plant, you can try increasing its indirect light so it can grow.
- Low light: Other plants like indirect light for a few hours a day.
Does indirect light have the same intensity as direct light? Indirect light usually does not have the same intensity as direct light and this will make it insufficient for direct lighting needs. The power of light coming through windows is already diminished in comparison to daylight. Even when plants are moved away from windows, the light intensity can also be reduced by half.
Are grow lights as good as sunlight? Grow lights have been designed to create the specific wavelength of light that is needed to encourage plant growth. To learn what you need to know about grow lights, click here.
You should always read your plants to determine what they need. Are they getting yellow leaves or do they have any burn spots? Try moving them to a spot away from the window. Do they look leggy and tall? Let them have more light so that they won’t expand to reach for the light.
When plants are given a stable environment around their ideal growing temperature range, they will then be able to perform better, reducing the risk of slower growth or of their ability to properly photosynthesize and may eventually die with wilt.
It is generally recommended to aim for a temperature where you are comfortable since most plants will thrive in this range. If you are someone who tolerates snowy weather in shorts and a T-shirt, “comfortable” is around 65-80°F (18-26°C).
Although this may not be the ideal temperature for the plant, it is likely within its optimal range. If you have a dedicated growing environment, then you can find out exactly what your plants need. Most houseplants need temperatures between 70-80°F.
Temperature for watering. When watering your plants, use room-temperature water so you don’t shock your plants. Get a watering can or get an old jug to make storing the water in the house easier.
Would putting your plants on a radiator or heat source be the best option? Sometimes as you have a cold house, it might not be the best spot in the house (for light or heat). The most advantageous use for this is for seed starting but if you are growing plants near a heat source, you must be more careful when watering them since the soil dries out faster.
In dry air, plants lose moisture that is impossible to absorb from the roots alone, so they need a certain amount of humidity. It’s kind of like trying to fill a bucket that’s got a leak.
The humidity ranges from 0% to 100%, with Arizona at 0% during winter and Florida at 100% in summer. Houseplants thrive at a humidity level of above 40%, especially during winter, whereas the humus levels in the average house are often lower.
- There are ways to slightly increase humidity around the plant besides purchasing a humidifier.
- Set up your plants as a group so that they have an environment that supports higher humidity levels.
- Put a shallow tray of pebbles on top of the plant so it will evaporate water. Take a small amount of water, then add the plant and set the tray on top of the pebbles.
- You should mist the leaves of your plants if they can tolerate it. Be sure not to wash them down with water – just a light spraying is enough to raise the humidity in the air.
Is there such a thing as too much humidity? Excessive humidity encourages mold and rot. You may find your plants require higher humidity levels than 60%, but if you exceed this limit, then you are at risk of mold growth. White mold can grow on the soil or the leaves. Check your plant for mold and if everything is okay, continue to grow it.
Many plants have different needs, so finding out more about them is the best thing you can do. Your sense of plant knowledge is likely growing stronger now that you know the basics and what’s important. Let us know if you wonder about anything else.