18 Common Indoor Gardening Mistakes [Personal Experience]
The most common mistake in indoor planting is ignoring the natural needs of the plant in terms of water, light, and soil. More often than not the beginner will do way more than is necessary. I am growing plants for 2 decades and these are quite often the most common mistakes I see people doing.
1. Watering Ignoring Seasonal Changes
Everyone might tell you that watering your indoor plants on the right schedule is a basic essential to keeping them alive. Except for the fact that a single proper schedule does not exist!
Here the mistake
Many people water their plants randomly or with a fixed schedule without checking their real plant needs which might change over time. This is by far the biggest mistake among gardeners. Nothing to be ashamed about, I sometimes did the same. You just need to know your plant better.
Here’s the deal:
Many people do a superficial visual check to see if the superficial soil is damp. This is often ineffective. Indeed, dry superficial soil does not imply dry soil at the root level (that can be several inches below the surface).
Then, what can you do right now to understand your plants water need?
There is a simple two-step approach that you can reliable apply to easily check the water requirements of your plants.
- Look at the plants: Are the leaves drooping, discoloring, falling off? This is a first (but not enough) indicator. Do not be fooled. Many might be the reason for such reactions (infections or bugs as detailed on this basil black spots guide.
- Taste your soil: Check the soil border close to the container. If the soil is pulling away from the sides of the pot, it’s probably dehydrated. You can feel the soil as well, but make sure to place your finger deep (2 inches beneath the surface) in the soil rather than just touching the surface.
This will give you a better idea of what the soil is actually like. If the fingers come out moist, you are ok, no water needed. If it feels wet, then you are in an alarming situation. Your plants are risking root rotting. Finally, if it comes out dry (you feel the soil powdery on your fingertips), then it is time for some water. Remember that some plants are drought not-tolerant (basil), while others enjoy a short period of dry soil (rosemary and sage).
2. Too Much Water
I bet that, like myself, you love having your container on top of a saucer. It is not a brainer to keep the floor clean and have everything tidier. Something wrong with them?
Here is the problem
How many times have you watered your plants without emptying your saucer straight after? If the answer is “I do not remember ” then your plants have a problem.
Indeed, especially in the case of well-grown plants, their roots can be quite long and reach the bottom (or close) of your pot. Hence, if the sauce is filled with water, the bottom part of the soil will always be wet and, as a consequence, also the roots in that area.
This will create the right environment for root rot bacteria to develop. Once such roots are affected, the disease might easily spread to initially healthy surrounding roots. This kind of bacteria is hard to fight with a common intervention, and more often than not, you have to through the plant.
What should you do?
Just empty the saucer each time you water. Here are a few tricks to make your life easier:
- Screw taps: place a few plastic screw taps (in my case, I use plastic bottle) between the container and the saucer. This will create a separation between the two and, even if you do not empty the saucer, now your plant will be fine as the water will not be in contact with the container anymore.
- Water the strictly necessary: stop watering straight after you see a few droplets coming from the drainage holes. Indeed, this is the sign that the water went through the soil that is not able to hold it anymore. Hence, any further watering is useless (and a waste of water).
3. Using Fertilizer When No Needed
Fertilizer provides the nutrients that your plant needs for growth. Everyone says that no? However, do you know when to add fertilizer? Perhaps the soil already has it, or maybe your plant at that specific moment in time does not need them!
Here are the 4 top mistakes in fertilizing:
- Excess fertilizer: Many think that the more fertilizer, the better. Totally, wrong! Overfertilizing is one of the most common gardening mistakes. Nutrient excess will lead to yellowing/browning leaves, wilting, weak stems, and lots of growth with no leaves. For the curious, I also wrote a guide on the most common over-fertilizing symptoms.
- Fertilize at the wrong time: fertilizer provides the minerals your plant needs to produce new fresh leaves. However, do your plants grow throughout the whole year at the same rate? No! Hence, you should not provide fertilizer at the same rate all year-round. More fertilizer in summer and no fertilizer in winter.
- Fertilize seeds: seeds are designed by mother nature to have all the nutrients they need to develop the first shouting and micro version of your plant. Indeed, in recent years they have also been used for eating purposes due to their high nutrient content (Basil, chia, etc…). Seeds do not need fertilizer.
- Fertilize on fresh potting soil: good quality potting soil contains a large variety of growing mediums. Among them, more often than not, you can find slow-release fertilizer on it. This is generally sufficient to provide those precious minerals (gradually released) to your grown plant or half a year.
- Choose “unbalanced” fertilizers when no needed: quite a few fertilizers have a way larger content of one of the three macronutrients (Nitrogen, Phosphorus, Potassium). More often than not, nitrogen is the one more abundant (think about Blood Meal, for instance). These should be used only if you are 100% aware (through some nutrient testing) that your soil is lacking mainly of nitrogen. However, this is not often the case. That’s why I usually prefer a more balanced mix as this one sold on Amazon.
Here is one of my tricks in using fertilizer.
First, just use a half dose of the amount of fertilizer recommended. For instance, the label tells you to add one teaspoon of liquid fertilizer per liter of water? Then use 2 liters of water for the same teaspoon of fertilizer. Then monitor your plant closely on a weekly basis to see how it is going.
Extra step? Take some pictures, week after week (perhaps on Sunday before having breakfast, just a quick snapshot, so it becomes a routine). This will allow you to track progress so easily and reward you for your plants’ progress!
Do you want to know more about how you should fertilize your plants? Click the image below for a full fertilize guide.
4. Wrong Lighting
Plants need light to produce the sugar and nutrients they need to survive. However, not every type of plant needs the same level of light.
Here the mistake
- Lack of light: I had in the past the tendency to overestimate the amount of light our plant receives. That corner in the shade, in the kitchen it is not dark, and it looks suitable for an plant. As a rule of thumb, any indoor plant requires around 6 hours of direct sunlight. The light reaches directly the plant (direct light is not shade!). However, plants do not have eyes, and they are very sensitive (and requiring) in terms of light. Placing your plants on a windowsill might not be enough, especially if it is not south-oriented to allow it to
- Excess of light: this is not a problem for the majority of you except during summer. If you live in areas with scorching 12 hours of more intense light (and heat), your plants are in danger. Indeed, not only the direct light will burn the leaves but also the heat that can build up in your living room or kitchen where you left your plant might easily build up leading to dehydration.
Instead, try this:
Do your research
Different plants require different amounts of sunlight. Whereas one species might benefit from extended sunlight, others perform better with less sunlight each day. When you’re deciding what plants to grow, make sure you know their specific needs.
Consider the light in your home: If you have a lot of natural light in your home, it’s a good idea to opt for plants that can leverage such resources as discussed by the University of Minnesota. However, this is not the case for many of us (like me living in a small apartment in a cloudy country like the UK).
Check the image below for an article on low-light demanding indoor plants.
Hence, in this case, If you don’t have the right amount of natural light, do not give up. Consider using grow lights, as discussed in this detailed guide.
5. Using Containers Without Drainage Holes
Have you bought a container for your plants without thinking? Perhaps because it looks pretty?
Well, you are not the first, not even the last. It is true that plants, in general, are not very delicate plants and so they will not suffer in case you do not pick the “ideal container” (that actually does not exist). However, a few common mistakes should be avoided when choosing your planter.
In shops and even online retailers, you can find pretty containers defined as “planters.” These are quite stylish and, without a doubt, a plant in them might look pretty good.
Here is the catch
If the container looks quite pretty, chances are that it does not come with drainage holes. Look for this one on Amazon, for instance. In a living room, it will look great; however, if you look closely at the pictures, no drainage holes are present.
Absence of drainage holes
Especially for plants, or moist-loving plants, this type of planter should be avoided. Indeed, the absence of drainage holes will lead your plant to die very quickly due to root rot, as clearly stated also by the University of Illinois and countless gardeners.
Inadequate container size
The container should suit your plant. This means that placing a seedling in a 20 liters container will probably lead to his death if you are not really careful with watering. Indeed, with such a massive volume of potting mix, the roots of your small plants will not be able, on their own, to dry the potting mix.
Hence, what would happen? Your plant’s roots will remain constantly wet as there is almost nothing to suck out of the soil a large amount of water the inner part of the soil contains. Constantly wet roots will lead to root rot and death.
On the opposite side, we have those gardeners that placed their plants in containers that are way too small. Is this a problem? Yes, because the soil will dry way too fast, and, more importantly, your plant growth is stunted. Your plant might survive, but it will stop growing.
Here is a detailed guide on basil container size if you are interested.
Here’s what you do:
Once again, you’ll want to start with research. Most household plants are comfortable in a 6-inch pot, but some dwarf varieties can be planted in smaller pots.
As plants grow, they may need more space. If you notice your plants seem to be outgrowing the pot you put them in initially, don’t be afraid to repot them in a more suitable container.
6. Using the Wrong Growing Medium
Is soil just dirt, right? Well, no.
To grow plants, it is essential to use a suitable growing medium and take care of it (with fertilization), especially when grown in a container.
Indeed, the lack of insects and small animals moving the soil (as naturally happens in an outdoor environment) in a container, makes the circulation of air and water (aeration and drainage) real issues on containers. These can be taken under control only with the right growing medium.
Hence, what mistakes are done with growing medium?
Outside gardening soil: this is generally way too compact for indoor gardening purposes, especially for plants that generally require aerated growing medium. Moreover, the presence of bacteria, pests, and fungi makes outdoor gardening soil dangerous for any plant you plant with it in a confined environment.
Compost, or other “individual material”: in this article, you can find a list of the most common material to produce a growing medium (including the one for your potted plants). What you need to know is that none of them, alone, can be used as a potting mix. For instance, using compost as a growing medium will not provide the physical structure that your plants need to develop. Moreover, compost deteriorates over time, making it difficult for any plant to thrive. A good growing medium is always a mix of multiple materials.
So, what should you use?
If you’re growing seedlings, it’s best to use a seed starting mix. This has the consistency to allow your seeds to receive plenty of water, oxygen, and be soft enough to allow the soft roots to move through it.
Once plants are past the seedling stage, you have to go for a potting mix. The better choice is because it compacts less and has better drainage. These either include peat moss or coconut coir, but coconut coir is superior and more sustainable.
Here is an article on the best potting mix for plants.
7. Planting Too Many Plants
How many of us started a new hobby (or going to the gym) with lots of enthusiasm?
I have been there. This is great. However, it has a (hidden and massive) drawback: overcommit and overdoing. This, due to inexperience, will lead to poor results that might pull off many of us, losing motivation and giving up.
Here the problem
Many new gardeners make the mistake of taking on too much responsibility when they start out. They start planting 4-5 or even more plants at the same time. Even worse, different plant plants at the same time.
Each plant has slightly different requirements. Some of them require watering like mint, while others enjoy dry soil like rosemary. In theory, you should treat them in different ways (watering, container size, location). However, if you are starting out, you just do not know, or simply do not have the time at first.
Instead, try this:
Rather than starting out with enough plants to fill your home, start out with one or two. Choose a plant that is perennial (last many years, so no replanting with you) and low maintenance. Mint, for instance, is one of my favorites. A quite strong and amazing addition to many plates (and even cockatiel). Start from a potted mint from a supermarket, or grow it from cuttings as discussed in this guide.
This will give you the time and let you gather experience on how to take care of plants before you step it up, adding more and more. Building your indoor garden over time is much easier when you’re starting out compared to starting out big.
8. Choosing Delicate Plants
Which plant should you choose to start? Are not they all equal? No!
You need to know that there are plants more resistant than others. When I say “resistant,” I mean that they are, for instance, drought-tolerant, they survive within a wide range of temperature or do require less light than others.
What does that mean for you? Less care, more room for beginner gardener mistakes as your plant will be strong enough to cope with them. You forget to water, and your plant will not wilt the day after. You leave it in your freezing kitchen counter during a winter day when you are not home (so heating off), and it will not wilt.
Here the mistake
Choosing your plant randomly or just because you like its taste on your dishes. How many times in the past, I attempted to grow basil indoors when I started out and wondered why it was dying all the time. My living room is just too cold (in the UK) and basil is quite sensitive to overwatering. Although many gardeners might tell you that basil is easy, remember where you live.
Something to keep in mind:
When you’re starting out, don’t increase the learning curve you’re handling when you start gardening. Instead, start out with plants that are easier to care for like lemongrass or mint. This will give you an easier period to learn the basics of gardening before the task of caring for the garden gets complicated.
Although I love herbs and houseplants, and this is my specialty, I also grow vegetables for my own consumption. I can guarantee that spring onions are extremely resistant and grow like a charm if you want to try something even easier.
9. Place Many Incompatible Plants in the Same Container
Do you have a large plant container that you want to fill with plants? Not so fast!
What you need to know is that not all plants can grow well together. Why? Mainly because of the plants of different water and soil requirements. Some of them (like mint) enjoy moist soil at all times while others (like rosemary) thrive in dryer soil. Place two plants with such different water requirements in the same container, and the results will be the death of one of them.
Another case is the presence of invasive plants. Mint, for instance, is pretty notorious for that. Its roots subtract nutrients from any other plant in the container.
Here’s what to do instead:
Do you want my 2 cents on the topic? If you are starting out, just avoid planting multiple herbs in the same container. It can be painful, especially if one of the two is suffering a disease like black spots on leaves in case of basil.
10. Reusing Old Potting Mix
Is your old potting mix reusable? Perhaps you thought that soil is just soil, so what’s the problem in recycling it?
Here the mistake
Using an old (1-2 years) potting mix can be a bad idea for several reasons.
- Compost degradation: a good quality potting mix has up to a third of organic matter (compost). This tends to decompose over time, changing the soil structure. This becomes more compact, reducing the soil aeration. You can also see the soil level on your pot getting lower over time.
- Pests or/and fungi: that soil was providing nutrients to a plant that died off? Perhaps this happened because of fungi? You do not know? Then, in this case, it is better to throw away the soil. Some spore of many common fungi that can easily destroy your plant can last for up to 5 years as detailed by Cornell University in this presentation.
Many plant diseases that can be carried out on soil can also cause black spots on your plant leaves, leading to a quick death if left untreated. If you want to know more about black spots (on basil and similar in other plants), click on the detailed photo-guide below
So, what should you do?
When you’re planting your plants, you should make sure to use fresh potting soil every time (or unused even if you bought it one or two years ago and stored it in a dry and cold place).
11: Lack of Pruning Regularly
Harvesting and pruning plans are more than just an aesthetic practice. Indeed, when some plants are cut in the “right spot” (like herbs) they tend to multiply the number of branches they produce. This is the case for basil, for instance, as you can read in these 21 practical tips to grow basil indoors.
If you grow herbs, do you harvest them only when needed for your plates or on a regular basis?
Here is the problem: Harvesting only when “you” need might be good for you, but it is generally not good for the plants.
According to the University of New Hampshire, different plants have different pruning needs. Rosemary and sage need pruning and harvesting every year to extend their life to another season. On the other hand, wormwood does best when kept at the height of 7 to 9 inches (17.7 to 22.8 cm). Once again, carefully research your plant’s needs as you choose them.
12. Growing Herbs That You Don’t Eat
A long-lasting motivation is key for growing an indoor garden! Easy to say?
When you start a new hobby, indoor gardening included, you are very keen on it as this is driven by a large enthusiasm for trying something new. However, this is always a short-lived burst of motivation.
Here is the issue
Many, when they start gardening, do not think about the reason for what they are doing? Do you like flowers? Do you like to know more about gardening? Do you want to make a trial on a small scale to then grow a more abundant gardener outside?
Whatever it is, you need to find your own reason! Mine? Easy, I want to grow only edible plants, and you should consider this too! Indeed, it has so many advantages:
- Great satisfaction in growing something that will end up on your plate.
- You are helping to reduce the consumption of plastic (packaging), carbon emission (transport) and chemicals (pesticide)
- You will become more creative with recipes (as you have to consume those plants);
- You will introduce those herbs in your diet. The majority of edible plants have a high vitamin and fiber content, definitely an excellent extra value for your diet.
13. Lack of a Caring Routine
There is something that goes beyond knowledge if you want a thriving indoor garden.
What are many indoor gardeners missing?
A routine! Indeed, watering and fertilizing are those long-term actions that you need to perform on a regular basis. You cannot water your plants “when you have 5 minutes” or “when you remember” (I heard this so many times). Forget once to water your basil (if you do once a week), and chances are that you might lose your plant.
Hence, what can you do to have a gardening-caring routine?
When you’re starting a new garden, take steps to make taking care of it part of your daily routine like brushing your teeth or making dinner, it’s a lot easier to remember to get everything done. How? At first, it can help to set reminders. For instance, set the alarm when it’s time to water your plants to remind you. Eventually, you’ll remember to do it without a reminder because it’ll be part of your routine!
Here my protip
Several studies suggested that to create a new routine, you have to use an old one as a trigger (this is the reminder). In my case, I use having my Saturday breakfast as a way to remind me to water the plants. While my eggs are frying (yes, love my scrambled eggs and salmon with my grown chives), I water my plants. It takes less than 3 minutes (I have just a dozen small pots).
14. Do Not Talk With Other Experts
You and I are limited by the amount of information we can remember or gather. However, out there, there are dozens of experts (more than me for sure) that will be more than happy to give you advice for free and sometimes almost instantly!!! Crazy?
Here is the problem
Many gardeners might not be aware of what the technology has to offer. There are plenty of great places where you can have free advice on any of your gardening problems. Do not be afraid to ask!
Indeed, many are expert gardeners that will be more than happy (just to help and share their passion), a beginner gardeners in difficulties.
What should you do?
Join one (or more, or all of them) of the following groups! I am part of all of them and, between one post and another, I also drop some reply here and there:
- Quora.com: here you can see, without registration question of other people. I am part of the indoor gardening section. However, you can check whatever you want.
- Facebook group – Indoor Gardening Tips/Ideas: very interesting to check how others get creative;
- Forum Garden Stack Exchange: this is one of my favorite forums. It is quite large and many experts over there as well ready to help!
15. Start From Seeds
Have you ever thought that growing herbs from seed is the true way to gardening? Well, sorry, but at least for me, it is not. It is true that it is a rewarding process seeing your herb go from a tiny spec of dust ( think about those minuscule chia seeds) to several cm tall herbs to harvest. However, there is a drawback, especially for beginner gardeners.
Here is the issue
Starting an plant from seeds is way harder than buying an already grown plant. This is because:
- A different growing medium: seeds generally need a high moisturized growing medium to the grown version of the same plant (generally). Moreover, depending on the type of plants , the roots can be very small and fragile. So, you cannot, in general, use the potting mix to grow seeds on it. You need a specific soil that is very airy, light, and with high water retention capabilities.
- A different container: seeds, for their high humidity, requires an enclosed environment. Hence, you need to buy a specialized container with a plastic lid like this one on Amazon. However, quite often, you can find both soil (jiffy pellets) and such containers together as this one. A good idea if you are starting out, a bit annoying if you already have the lids, and you just want the soil.
Pro-tip to save a few dollars: just recycle those small plastic containers used for milk or spreadable cheese (I usually use those for cottage cheese). The 250ml ones are more than enough as they also have a transparent lid that is far enough from so to allow 2-3cm, and they are at least 6-7 cm tall (3cm of soil land 3cm remaining of space for the seedling to grow).
- Temperature: seeds, to sprout, also require a relatively high temperature from 68 to 86F (20 to 30C), as discussed in this scientific analysis. These are not temperatures you have indoors, not even in summer (as you might turn on the air conditioner). So, in this case, you might need either a greenhouse or a seed heating mat.
- Transplant: after the seeds sprout originating a few cm tall plant, it is time to migrate them to a larger container with a potting mix. This means you get dirty and a bit of maintenance (and delicate hands if you do not want to damage the seedlings roots).
- Time: seeds require time to sprout. Hence, it is not uncommon, depending on temperature, water, that it might take 2 or more months to have your very first leaves harvested to drop on your dish.
16. Using Bad Quality Soil
When you start a new hobby quite often, you need to invest a bit of cash upfront. Either for tools or education (ideally both). Although there are shortcuts for that, a small investment is always inevitable.
Here the problem
Not investing $20-30 to buy the essential:
- At least one container with drainage holes: check these ones, quite cheap from Amazon (here a good one), and do their job. I would go for a 6-7 inches diameter. Most plants are fine with it.
- A good quality potting mix: if you are unsure, check this detailed guide on the potting mix. If too big you can always find other smaller solution, but I would go for that brand if possible, quite well-known among gardeners. Remember that a 6-inch container requires around 2 quarts of potting mix (around 2 liters).
- Grow light (perhaps): this is a whole topic of gardening. However, if you want to grow plants inside, but you do not have the chance to have 6 hours of direct sunlight, your plants need to grow lights. Direct sunlight means that your plants receive light directly from the sun, without any reflection (your plant , if it would have eyes, will see the sun directly). However, you do not need to break the bank. For around 10 to 30$ you can have a decent grow light, more than enough for a couple of potted plants.
Here’s what you should do:
When you’re starting your new garden, start with the basics and invest in what you need for your plants to thrive right away. This is another reason to start small. Make your life easier and spend less.
17. Ignoring the Growing Medium
Does the soil change over time?
Yes, and quite often significantly. Many are the reasons. The nutrients have run out (potassium, phosphorus, and magnesium), or the acidity (pH) increased due to the decomposition of organic matter.
Here the problem
You leave the soil for many years unchecked. This will inevitably affect your plants. A different pH will impact the way nutrients are absorbed.
Check the article below (click the image) to see if your plant is suffering from one of those symptoms.
Another problem might be that it runs out of nutrients. Also, the decomposition of organic matter present in the potting mix will inevitably affect its structure of it (making it worse). Quite common is for the potting mix to get way denser (compact). This is not good as it limits the aeration of your herbs.
What should you do then?
- Is your potting mix, used by a plant for no older than 6 months? You are fine. No action needed;
- If the answer to the previous question is no, then I would start checking the soil. Is the soil surface lower than it was initially (you will notice some sign on the side of the planter)? If the soil lost volume is a sign that needs to be changed.
Does your plant show some sign of distress after you carefully checked that the light is ok and there are no pests? Check this detailed guide (pests section). If so, just do a quick test of your herb.
Testing your soil for nutrients. The nutrients you want to check on your soil are phosphorus, calcium, potassium, and magnesium. If any of these are low or not present, the soil won’t offer the proper balance of nutrients. Here is an article to guide you through the soil testing world. If you want a quick solution, just check this quick soil test that you can use from your home quite easily. Such tests also have a pH section.
18. Use Insecticide Too Often
Have you found some pests on your plants? Well, you are not the first, not even the last gardener to deal with this.
However, you might be one of the many to use an insecticide in large amounts (or even when not needed).
Here the problem
Having pests on your plants does not imply for you to run to the first supermarket and start submerging your plants with chemicals. Why?
A few insecticides are not suitable for edible plants. Have you checked that?
Some insects can be removed just by shaking the plant and some jet of air (hair dryer at cold temperature). Beetles or whiteflies if in a low number
Often you can find some chemical-free alternative where a bit of vinegar or soap can be good enough to eradicate a small invasion of pests
What should you do?
- Do your research. Surprisingly, there are some plants that work as natural insecticides. According to the International Research Journal of Pharmaceutical and Biosciences, plants like mint naturally keep bugs away.
- Use chemical pesticides and insecticides carefully. Most sources recommend using chemical insecticides as a last resort and sparingly when used. If you are using them, it’s a good idea to wash anything you use three times and keep your plants away from pets and children.
- Check for natural alternatives. Vinegar and soap make miracles for many insects as the good video below shows.
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