Indoor Gardening For Beginners: Basics You Should Know

However, if your plant is growing great and then looks sickly, that could be a sign that your roots need room to grow to support the plant. Now would be a good time to repot the plant.

Indoor Gardening Systems: Endless Plant Possibilities

Gemma Johnstone is a gardening expert who has written 120-plus articles for The Spruce covering how to care for a large variety of plants from all over the world. She’s traveled all over Europe, living now in Italy.

Kathleen Miller is a highly-regarded Master Gardener and horticulturist with over 30 years of experience in organic gardening, farming, and landscape design. She founded Gaia’s Farm and Gardens, a working sustainable permaculture farm, and writes for Gaia Grows, a local newspaper column.

If you don’t have access to suitable outdoor space but still want to cultivate a selection of fresh veggies, herbs, or other plants, you might want to create an indoor gardening system. The system you use depends on how ambitious you want to get, what you plan to grow, your budget, and the available space. Indoor gardening is ideal for apartment living, if your outdoor soil is not workable or if you don’t have time to manage weeds and pests.

Learn more about creating a flourishing indoor gardening system in this beginner’s guide.

What Is Indoor Gardening

Indoor gardening relates to the act of growing a selection of plants inside that you would typically grow outside. Because you can more easily control temperatures and other conditions, you can access things like veggies, fruit, herbs, or tropical plant species year-round, unlike in many outdoor gardens when the temperature determines the growing season.

Plants for Indoor Gardening

Certain plants are known for being well-suited to being grown indoors. These include:

• Veggies. Some veggies grow particularly well indoors. These include carrots, hot peppers, lettuce, and tomatoes.
• Herbs. Basil, chives, mint, parsley, and thyme are just a few herbs that do well in a sunny position indoors.
• Low-Light plants. If you want to create a low-maintenance tropical jungle in a shady area in your home, opt for low-light species like spider plants, snake plants, and certain ferns.
• Humidity-loving plants. Consider things like begonias, ferns, and peace lilies if you want plants for a terrarium or to grow in a bathroom.

Common Types of Indoor Gardening Systems

The indoor gardening system you select depends on the type of plants you want to grow, your budget, available space, and your preferred aesthetic. Below are some of the common types of indoor garden systems.

Soil-Based Systems

Allows you to grow your plants in containers with potting mixes. It is the closest to traditional, straightforward outdoor gardening and is an economical option, often used for cultivating a herb garden or displaying a selection of tropical plants.

Hydroponic Systems

Hydroponic gardens allow plants to be grown in water rather than soil. The water contains essential nutrients, and some include substrates like perlite, vermiculite, or coconut coir. It’s a bit pricier than traditional soil-based setups, but it maximizes space, conserves water, and produces fast-growing, healthy, and high edible plant yields.

Aquaponic Systems

Aquaponics is similar to hydroponics and shares many of the same benefits, but it is less widely used. These systems involve keeping live fish in the water. Their waste is full of nutrients that help the plants flourish. If this doesn’t gross you out too much, be prepared for a more pricey initial setup and ensure the plants you pick are happy in this wet environment (leafy greens are a popular go-to).

Aeroponic Systems

This advanced hydroponic-style system sprays nutrient-infused water on suspended plant roots rather than fully submerging them in water. This method allows plants to absorb the maximum nutrient levels promoting fast-growing, large yields. However, it is challenging and costly to set up.

Terrariums

Try a glass terrarium if you want to grow a selection of humidity-loving plants without taking up much space. You can select plants that are low-maintenance while still visually appealing. Terrariums come in a wide range of sizes and prices, so there should be something to suit every enthusiast.

Living Walls

If you have limited floor or shelf space or want to liven up a bare wall in your home, creating a vertical living plant wall could be the way to go. Select plants with similar care requirements as you will water them all together.

Tip

A wide range of plug-in-and-go indoor gardening systems is available from major retailers. These typically include handy features such as built-in auto-timers, grow lights, and self-watering capabilities. You can save money not having to buy all the elements separately, and the kits are easy to assemble.

Indoor Garden Plant Care

The conditions your plants require vary depending on the type of indoor garden you want to cultivate and the individual species you select. Here are some general tips to consider when it comes to their care.

Light

Where you position your indoor garden depends on the plants’ light requirements. Plants grown indoors will never have access to the same direct bright sunlight they could get outdoors; even sunlight streaming through a window is less intense than it is outdoors. You may need grow lights to help create the right conditions for major sun-loving plants indoors or if you don’t have any natural light in an apartment. Conversely, if you have true shade-loving plants, keeping them away from windows will be necessary.

Soil

If you aren’t opting for a hydroponic setup or collecting air plants, your indoor garden will generally be best grown in a loose, well-drained potting mix. The mix can be tailored depending on what you grow, but it is often composed of peat moss, vermiculite, and perlite. This combination absorbs moisture quickly and doesn’t become easily compacted. However, it will dry out quickly, so it won’t work for moisture-loving plants like basil.

Water

Of course, every plant grown indoors will have differing requirements in terms of watering. However, one of the biggest common problems for indoor gardens is overwatering. Many indoor plants die as a result of root rot.

Always research what the plant species you are growing needs. Watering your plants with room temperature water is also a good idea. Cold tap water can shock your plants.

Fertilizer

Ensuring your indoor garden plants receive enough nutrients is important for long-term success. Although some potting soils have nutrient enhancements, the plants will use them up after a couple of months. Slow-release fertilizers are popular as they can last several months before another application is required.

Temperature and Humidity

Being able to control the temperature and humidity in an indoor environment is one of the key benefits of indoor gardening. The ideal humidity level for many indoor plants ranges from around 40 to 60 percent humidity.

If you have moisture-loving plants that need high humidity or your living space is particularly dry during the winter months when the heating is on, you could invest in a humidifier or set up the garden in your bathroom. You can also use indoor greenhouses or terrariums.

Repotting

Repotting your indoor garden plants in soil-based systems annually, or when they are becoming root bound, is vital for long-term growth and health. Make sure the pot is big enough for future growth.

Indoor Gardening For Beginners: Basics You Should Know

If you are blessed with a natural green thumb, 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.

Save yourself some of the hassles by understanding the principles of what’s going on above and below the dirt. While you could come back to this after killing many of your plants, why not start out with an indoor gardening guide to give you all you need?

We’ll take a look at how plants grow, then dive into actionable tips on what you need to do to promote healthy growth, even as a beginner. Anyone can learn how to garden indoors!

How Do Plants Grow?

Most likely, you will buy a plant from the store or acquire it from someone else already fully grown. And while we’ll cover adult plant care a little further on, let’s start at the very seed of the process – from the seeds themselves.

Growing a plant from seed is a wonderful process, and armed with some indoor gardening basics, it’s pretty easy too.

Stages of Plant Growth

There are definitely stages to the growth of every plant. We don’t usually think about them a lot. You stick a seed in a pot, and a plant appears, right? But there are different needs at each stage which should be met.

The seed itself is a fascinating thing. In one little shell is contained not only the beginning of the plant but what it needs to sustain itself until it can form a root.

A seed has three “basic” parts: the seed coat, the endosperm, and the embryo.

When we look at a seed, we see merely the seed coat. This thick exterior protects the future plant.

From there, the endosperm provides all of the nutrition the plant will need initially. This completely surrounds the embryo in most seeds, providing easily-accessible sustenance. It’s not just for plants — we eat endosperms too! Anyone who’s had popcorn or white rice has munched on delicious endosperms.

Finally, there’s the embryo itself. There are three major components to an embryonic plant: the roots, the cotyledon, and the embryonic leaves. All of these are tucked inside that tiny little seed.

We all know what roots are, of course. The cotyledon is an external food source for the plant once it emerges, and the embryonic leaves are usually the first two leaves that appear once the seed germinates.

If you store your seeds in a dry, airtight location, they won’t move on to future phases until conditions are right. Seeds can be viable for years, although the endosperm will gradually decline over time and reduce germination.

Germination

Germination is when the seed stops being shy and comes out of its shell. Two conditions need to be met for a seed to germinate:

• Water. Seeds soak up water and rehydrate, which triggers the growth process.
• Warmth. Different plants require different levels of heat to germinate properly. If it’s too cold or too hot, the seed will decide to stay dormant.

Germination can take anywhere from a few days for most vegetables to weeks for some trees. Here’s what can inhibit germination:

• Planting the seeds too deeply. Make sure to follow the instructions with your seeds, and don’t just throw any amount of soil on your plants. Some seeds can be placed on top of the soil. Others want to be under the soil’s surface.
• Poor quality seeds. Seed manufacturers have to test their seeds for germination rates to ensure they aren’t selling a bunch of duds. Stick with organic and non-GMO seed distributors to ensure the highest quality. And if you have leftover seeds from a previous season, test a small handful of the seeds – if they germinate well, then go for it.
• Too much or too little water. Most seeds like evenly-moist soil to sprout in. If it’s too dry, they’re not going to germinate. Too much water can actually drown the young plant!

When the seed first germinates, it relies on its endosperm for initial growth. It sends the root into the ground to establish a support system that will draw upon nutrients from the soil to allow it to grow further.

Now that the seedling has grown its roots downward to absorb soil nutrients, it needs to stretch its leaves so it can start gathering light to produce the energy it needs.

During the vegetative stage of growth, plants grow their stem, branch, and leaf areas to reach light areas. They grow more leaves and bigger leaves, so they have a greater surface area to absorb light.

While doing this, they’re hungry for nitrogen (N on the N-P-K fertilizer labels) to produce chlorophyll, the material that allows the plant to absorb energy from light. Fun fact: most chlorophyll is green, giving many plants their green color!

Reproduction

The reproductive phase is when the energy that was going to plant growth is now dedicated to flowering or going to seed. During reproduction, phosphorous is an important nutrient, as it assists with flowering or fruit growth.

This phase can be triggered by a change in the length of daylight. Plants are sensitive to these changes, and the sensitivity itself is called photoperiodism.

But plants just notice light itself, not where it comes from. That’s why artificial lighting can be used to control growth of plants indoors. As long as there’s a good spectrum of light that’s similar to natural sunlight, your plant will grow.

In this stage, you will also find pollination, which is how plants start to develop seeds and reproduce. If you have an indoor garden that needs to be pollinated, that means you have to pollinate them yourself.

Most people do this with a cotton swab, gently brushing it against the interior of a flower and then moving on to the next flower and the next. It’s not a difficult process and isn’t necessary on plants you don’t want to fruit or that you’re not collecting seeds from.

People who grow perennials (plants that live more than a year) know about dormancy. It’s a stage of the lifecycle that’s often overlooked since annual plants don’t have it, but it’s good to know about. In this stage, a plant can suspend its growth until a better growing environment is achieved.

You can think of this as a type of hibernation during the winter months or the summer heat. This period of dormancy can make them look like they are dying. However, they’re conserving energy until an opportune time. Smart little suckers, right?

Dormancy happens naturally as seasons change due to lower hours of light during winter and colder temperatures. For cold-loving plants, dormancy can also happen through the summer months, and the plant will come back once the heat subsides.

Indoor plants might not have as much of a winter dormancy period as outdoor plants, but it can still occur from December – February in the U.S. Thankfully for us, summer-dormant plants seem to like our cooler temperatures indoors, so they may not go dormant at all.

During dormancy, withhold fertilizer and water less because the plants will not be taking up as much compared to the rest of the year.

If your plants really decline when you start giving them less water + nutrients, then they probably aren’t going through a dormant period, and you should treat them normally.

By now, you have a good understanding of the stages of growth! So let’s jump into other critical information about how a plant grows.

Understanding The Roots

While we may admire a plant or tree for what’s above the ground, what’s underneath the ground is where the magic happens.

Roots are the IV of the plant. They absorb the air, water, and nutrients from the soil and transport them to the leaves for photosynthesis (which is how they produce their energy to grow).

If the roots don’t have adequate space to grow, then the plant, tree, whatever it is, will reach a certain size and not be able to grow any further. It’s like limiting your calories to only what your body needs to maintain the same weight. Since you aren’t getting any extra calories, then you can’t grow.

However, if your plant is growing great and then looks sickly, that could be a sign that your roots need room to grow to support the plant. Now would be a good time to repot the plant.

On the flip side, indoor gardeners can run into issues where they have too much space for the roots to grow.

Too big of a container is called “overpotting”. The problem is not with the roots but, ultimately, with too much soil. Whenever you water your plant in a larger-than-needed container, the water sits in soil that can’t be absorbed by the smaller root system. This reduces the aeration of the soil and causes the roots to rot rather than expand. It doesn’t happen in nature because the soil drains much better.

And what happens if you damage the roots of your plant? The good news is that a plant can regrow its roots if damaged. The key is how much of the root system is damaged. If there aren’t enough roots for the plant to draw in enough life (water, nutrients, air), then the plant will wither.

Understanding The Leaves

Leaves are biology’s masterful solar panels that convert light to energy for the plant. If you want to get into the technical details, the process of photosynthesis actually produces glucose which fuels the plant. But you remember that from school, so we don’t need to get into that , right?

Leaves are actually wonderful communicators. The problem is we are bad listeners. Here’s how to know what your plant needs by listening to the leaves:

• Starting to turn yellow? Your plants need less H20 or more nutrients! First, try watering your plants a little less often but still giving them enough water (don’t punish them for turning yellow on you). If they continue to turn yellow, then that could be a sign of a nutrient deficiency, and they will need some plant food or an organic fertilizer.
• Brown and crunchy? Your plant needs more H20! Don’t overwater them but make sure the soil is damp. Find the right consistency of water where the soil continues to dry up but the leaves aren’t turning brown and crunchy.
• MIA (Missing in action)? Your plant needs more H20 or sunlight! When there isn’t enough water or sunlight, your plants can’t do photosynthesis and so will not develop any new leaves or grow. Test giving your plants some more water first. And if that isn’t working, then try getting them some more light as well.
• Developing yellow spots? Pests can get to indoor plants just like they can to outdoor ones. If your plant’s leaves are starting to form yellowish spots, you may have a spider mite problem. Scale also can happen indoors and can cause other problems.

What Do Plants Need To Grow?

First, let’s look at the scientific requirements.

The 5 Things Plants Need To Grow

• Light. Plants use light as energy to turn water, carbon dioxide and nutrients into the sugar that they can eat, a process known as photosynthesis. When they have low levels of light, they can be starved because there is no energy for them to make their own food.
• Water. Needed to perform photosynthesis and enables the plant to draw nutrients from the ground. Water also provides necessary humidity around the plants.
• Carbon Dioxide. Plants breathe in the carbon dioxide in the air around them to use for the photosynthesis process.
• Growing Medium. Most commonly soil, plants need something to dig their roots into so they can hold themselves upright and draw upon nutrients from the growing medium.
• Nutrients. Just like humans need nutrients for good health, plants require nutrients that provide a variety of functions, such as aiding photosynthesis or helping them build a strong root system. All plants require different levels of nitrogen, potassium, and phosphorus to live.

Now that you have your fundamentals down let’s jump into the actionable tips.

Soil + Fertilizer

Soil is dirt that is “alive”. It contains nutrients, organic matter, water, air and even living organisms like bacteria or fungi. The soil is necessary for indoor plants so they can draw upon the nutrients in the soil to live. Dirt is “dead” matter and has nothing to offer them.

What soil should you buy? For indoor gardening, it is highly recommended to use an organic potting soil rather than soil from your garden which can bring pests and plant diseases into your home or greenhouse.

How long does soil last? Check the “Best if used by…” date… okay, I’m kidding, but strangely enough, many brands of potting mix do include a date like that! Soil can still be usable years down the line, but the nutrient content might be depleted from microbes eating it. Refer to the fertilizer section on ensuring the soil will have the nutrients it needs.

How should you store your unused potting soil? When not in use, put your soil in an opaque tub and put the tub in a stable, dry area like a garage or basement. You don’t want the soil to get wet, and you don’t want to keep it in an area where it can get common garden pests or become infected with bacteria. Check your soil every few months to make sure it’s in good shape and isn’t spontaneously growing anything.

Fertilizer is a concentration of nutrients to replenish the original nutrient content of the soil. If you don’t understand why that’s important, reread the “how do plants grow” section.

Fertilizer can come in many different shapes and sizes: it could be a packaged fertilizer, maybe some worm poop, and even your own poop could be fertilizer (that’s why I said many different shapes and sizes…too far, sorry).

For the basics, most fertilizers are talked about in “N-P-K” which stands for Nitrogen, Phosphorus, and Potassium, the essential nutrients for a plant to grow. Different fertilizers can have different NPK ratios to feed different types of plants.

What fertilizer should you buy? It depends on the plant, but the best bet is to get organic fertilizer. These are made to improve your soil over time, unlike synthetic fertilizers, which can slowly degrade soil quality.

How should you apply fertilizer? Water your plants before you add dry fertilizers so they are ready to absorb the nutrients. Follow the instructions on the package on how often you should use the fertilizer.

• If you are using a packaged fertilizer not specific to indoor gardening, consider using only 1/4 to 1/2 of the recommended dosage since you’ve got a smaller amount of soil to fertilize.

Liquid fertilizers can be used when diluted to a houseplant strength (check the label) and should replace regular watering.

Should you “flush” your plants? Fertilizer nutrients get absorbed by the plants, but other parts of the fertilizer will sit in the soil, which can have adverse effects. If you have drainage in your pots, consider heavily watering them and letting them fully drain out monthly. This will flush out the extra fertilizer parts and keep your soil healthy.

Water

I don’t need to tell you that you need to water your plants. But because overwatering is the most common cause of death for indoor plants, let’s make sure you are watering your plants not too much, not too little, but just right.

When should you water? Don’t focus on how often; focus on how much. Pay attention to the leaves as mentioned in the How do plants grow section. Also, pay attention to the soil. Does it still look wet? Does it still feel wet on top, or if you stick your finger in the soil?

You don’t want to keep watering the plant if it’s still wet. The water needs to drain so that way it doesn’t become stagnant and lead to mold. If you put way too much water in your container, then you risk drowning the plant, too, because the plant’s roots still need air.

How should you water your plant? Some plants do best with bottom watering (with moisture “wicking” through the soil), while other plants will do best with pouring water directly on the top of the soil. As it depends on the variety, research what will work best for your specific plant. When in doubt, opt for bottom watering, as the biggest roots should be able to reach.

Do you need drainage? If overwatering is the number one cause of death for indoor plants, drainage could be argued as the number one lifesaver for indoor plants. Drainage accounts for your mistakes in watering. The rule of thumb is that you should absolutely incorporate drainage if you can. Some plants are easier to take care of so you can risk it if you’d like, but it is easier on your if you just have some sort of drainage hole.

If you don’t have any drainage, what should you do? Be conservative in how much water you give your plants, and pay attention to how long the soil takes to dry. Does it dry within a few days? That’s good for most houseplants. If the soil stays wet all week, then that’s a sign you need to figure out a better solution for improving airflow or watering less.

If you are growing vegetables or microgreens indoors, you want dry soil sooner than a few days because they are more prone to developing mold in a shorter time frame.

Keep in mind, it’s easier to bring back a dying plant from underwatering than a dead plant from overwatering.

Air Flow

Ah, you can’t talk about watering without talking about air flow. Airflow and water are the two major influencers of plant mold and diseases. Air circulation enables water to evaporate quicker and prevent mold growth which is essential when you are growing your own food indoors.

How much air flow does a plant need? You don’t always need to have a fan blowing directly on your plant, but the easiest way to tell if you have enough air flow is by monitoring how fast the soil dries up. If the soil is taking longer to dry than it should, experiment with improving the airflow to understand if that is the best solution for you to get your plants to dry sooner.

How to improve air flow? You can be creative, but here are a couple of ideas. Keep the ceiling fan on in the room every once in a while, or open a window if it’s warm enough. Keep the plant near a window because the changes in temperature throughout the day will create a light “breeze.” You can also take the plant outside during the warmer months for a few hours during the day to get some better airflow .

Light

Light influences more than photosynthesis, it can also influence the reproductive growth stage, which is the time when the plant is ready to produce flowers, fruits, or seeds.

For most plants, you can control growth by manipulating how much light you give your plants. This can be especially important if you are growing vegetables such as lettuce which becomes bitter and edible when it goes into the flowering stage.

How much light do your plants need? Since this depends on individual plants, look specifically for how much your plant needs. Plants will generally fall in this range:

• Direct light: Some plants require hours of direct light daily in order to grow strong. This means that the sun is shining right on them, even if it is through a window.
• Indirect light: There are two situations when you want indirect light. The first is when a plant prefers indirect light because they are sensitive to too much direct light. The second situation is when you don’t have access to direct light, so you can try increasing how much indirect light you can give the plant so it can grow.
• Low light: And then there are some plants that do well with only a few hours of indirect light a day.

Is indirect light as strong as direct light? Indirect light will usually not be good enough for direct light needs because it does not have the same intensity as direct light. Light coming through windows is already weaker than regular sunlight. The light intensity can also be cut in half even with the plant being moved a couple of feet away from the window.

Are grow lights as good as sunlight? Grow lights have been engineered to produce the specific wavelengths of light needed to encourage plant growth. We have an excellent guide on indoor grow lights .

Remember to read your plants; they will tell you what they need. Are they getting yellow leaves or any burn spots? Maybe try a spot not as close to the window. Are they looking long and leggy? Get them some more light so they don’t continue to grow to reach for the light.

Temperature

Plants perform best in a stable environment around their ideal growing temperature range. If you let your plants get too hot or too cold, then you risk slowing down their growth or inhibiting their ability to photosynthesize properly which can lead to wilting or a crunchy (dead) plant.

Generally, the best temperature to aim for is one where you are comfortable because most plants can grow in this range. “Comfortable” is around 65-80°F (18-26°C).

Even if this is not the ideal temperature for the plant, it’s going to likely fall within their range. At these temperatures, you are happy, and your plants are happy. Most houseplants will likely be in the 70-80°F (21-26°C).

Temperature for watering. When you water your plants, use room-temperature water so you don’t shock your plants. Clean out an old jug or get a watering can to make this easier to store water in the room.

Should you keep your plants on a radiator or heat source? Sometimes the best spot in the house (because of light or because you have a cold house) is going to be on a radiator. This is ideal for seed starting, but if you are growing plants on a heat source, you need to pay closer attention when watering your plant since the soil will dry out faster.

Humidity

Most plants need some humidity to survive because dry air causes them to lose moisture that is difficult for them to absorb from their roots alone, kind of like trying to fill up a leaky bucket.

Humidity is rated from 0% to 100%, with 0 being Arizona during winter and 100 being Florida during summer.

The average house is commonly under 30% humidity, especially during winter, whereas most houseplants thrive above 40%.

How to increase humidity? Besides getting a humidifier, there are ways to increase the humidity around the plant slightly.

• Group your plants together so they have a microclimate around them that supports a higher humidity level.
• Create a pebble tray that encourages water evaporation near the plant. Take a shallow tray and place pebbles in it, then add a small amount of water and set the plant on top of the pebbles.
• If your plant can tolerate misting on the leaves, then mist the leaves periodically. Be careful not to soak the leaves – very light spraying increases the ambient humidity.

Can you have too much humidity? Very high humidity levels for extended periods can encourage mold and rot. Your plants are more likely to need higher humidity levels, but if you are increasing humidity past 60% when they don’t need it, then you might run into problems. White mold can develop on your soil or even on the leaves themselves. Pay attention to your plant for mold; if everything is good, keep on keeping on.

Did you notice all the times I said, “it depends on what plant you have”? The best thing you can do is research your specific plant types and take care of them specifically as they prefer. Different plants will have different needs!