How to grow herbs – 13 mistakes to avoid and what to do

I get a lot of questions about how to grow herbs and vegetables from friends, family and fellow enthusiasts.

As I like to test new methods and varieties I always have labelled pots around. This seems to encourage people to think beyond simply planting a seed and adding water.

Here today I will share my top 13 mistakes that I see people making when they grow herbs at home.

1. Buying herbs at the supermarket

Be patient and see the beauty in the process.

Grow your herbs from seeds unless you are in a real hurry. There is no reason to buy herbs in pots at the supermarket unless they are for immediate consumption.

It may seem like a quick fix to buy a potted herb plant at the supermarket. But why?

It is not difficult to grow herbs from seeds. And it can even be more difficult to grow a plant from the supermarket. 

These plants have often been driven hard under extreme conditions to make it to the supermarket shelf as fast as possible. 

How will you replicate this environment?

There are however exceptions to the rule. Basil is one herb that can be started by taking cuttings to grow more basil plants with ease.

2. Using old seeds

When people ask me how to grow seeds at home I give them the basic information about pot, soil, seed, light and water.

I often get the response that they think they have some bags of seeds in a drawer somewhere at home. 

This is not the right way to start.

It is possible to store most seeds for several years. If the seeds are stored properly. 

Seeds need to be stored in a cool and dry place with no direct sunlight and a somewhat constant temperature. 

If you are not sure that your seeds are healthy you should always buy new seeds to maximize your chances of germination.

And if you insist on using seeds left over from last year (or earlier) – always pre-germinate your seeds before planting. This way you will know that you are only working with viable seeds.

3. Watering too much 

It is easy to love our plants a bit too much.

And from my experience more herbs are killed by watering too much rather than not watering enough.

There are many different ways to gauge when you need to water your herbs.

If the weather has been really hot and sunny your herbs may need a bit of extra water.

You can also insert your finger in the soil and if it is dry 3 centimeters (1 inch) down it is time to water.

You can also buy a Soil Moisture Meter that will give you a reading of dry, moist or wet.

My best tips are to remember 3 things:

  1. dry on the surface does not automatically mean time to water
  2. water thoroughly and seldom rather than a little 3 times a day
  3. If you are unsure, do not water. Most herbs prefer a mild dry out to soaking wet soil.

4. Using big pots

There is no need to use big pots and lots of soil when we plant seeds.

Instead you should start your seeds in small starter pots. 

Smaller pots make it easier to control moisture levels. Simply water using a spray bottle and cover the pots with a translucent cover.

Let the seeds germinate and grow first and true leaves before even thinking about transplanting the seedling to a larger pot.

Smaller pots means less soil and more control. And this is a good thing.

5. Do not plant one seed per pot 

We have all seen the photos on social media. A pot with a solitary seedling growing proudly in the middle.

Why?

First of all, not all seeds are guaranteed to germinate.

And when seedlings develop they give each other support as they grow.

Furthermore, even if you do end up with too many seedlings it is so easy to thin out the plants and add the harvest to your next meal.

My tip is to always plant 5-10 seeds in a pot. 

Most herbs take well to growing in bunches. Examples are basil, parsley, thyme, chives, oregano and dill to just mention a few. 

6. Trim and harvest continuously

Herbs will grow long and top heavy if left alone.

Instead continuously harvest (remove) leaves to shape a healthier, bushier and more compact herb plant. 

Do not always trim the largest and oldest leaves on top of the plant. These leaves are your solar panels feeding the growth of your plant.

How to grow basil from cuttings
Basil cuttings setting new white roots

Harvest the younger leaves and, most importantly, look at the plant before you harvest leaves. You will see where it makes the most sense to harvest at any given time.

Another tip is to harvest 10-15 centimeter (4 to 6  inches) long cuttings from your herb plant. 

Harvest the lower leaves and leave the top crown intact. Place the stem in a glass of water and in 1-4 weeks you will see new roots forming.

Now simply plant the cuttings and you have started a new plant. Try it with basil or sage if you are new to the method but it is very easy.

Just make sure to replace the water at least every other day or so.

7. Are you providing enough light?

Herb plants need light to grow and thrive. 

Make sure you place your herb plants in a place with access to sunlight. 

A window sill can be an ideal place.

If you are growing herbs indoors during the darker periods of the year you should consider using grow lights.

I use a timer to give my herbs additional light from midnight to 8AM as the electricity is cheaper at night where I live. This also means that any natural light during the day is a nice and welcome bonus.

8. Watering the wrong way

Seeds and seedlings are fragile and need to be treated gently.

When we water from the top we risk flooding the planted seeds. Seeds that are planted on the surface will be displaced and often end up in one and the same place.

Seedlings showing first or even true leaves will also be flooded and we risk exposing roots as the soil shifts. The leaves can also be weighted down and pushed into the soil.

My tip is to always water seeds with a spray bottle. Seedlings are on the other hand watered from underneath using a water bath.

Watering from underneath will allow the soil to absorb moisture while leaving the surface intact and undisturbed.

9. Using the wrong soil 

Sometimes more is not better. 

And this is definitely true for planting seeds and the use of fertilizer.

Seeds and seedlings do not need a lot of nutrition to develop during their first stages.

If you use regular garden soil you risk adding too much fertilizer. This is not necessary. 

Regular garden soil is also often too dense. You want a looser solid to allow the seeds and seedling to grow and develop.

Ideally you buy or mix your own potting soil. If you do not want to spend money you can also use 2 parts of regular garden soil mixed with 1 part of coarse sand.

Throwing in a handful of gravel will also help make the soil more porous if available.

10. Allowing herbs to flower

You should never let your herbs bolt or flower.

Unless of course you are planning to harvest edible flowers, or seeds for the next growing season.

When herb plants set flowers a couple of things happen.

The two most important to us are:

  1. The taste of the herb changes. Sometimes the herb will lose some of its characteristic taste and smell. Ther times the taste may change and turn bitter.
  2. The plant will now use all its energy to produce flowers rather than the leaves we are looking to harvest.

My tip is simply to trim any buds or flowers as soon as they appear. 

Now if an annual herb has started to bolt is it not possible to reverse the process. But we can delay it by removing buds and flowers as soon as we see them.

11. Not growing seeds in batches at different time intervals

If you want to have fresh herbs in your kitchen garden year round, then do not sow all your seeds at the same time.

Instead, sow seeds in batches, every 3 to 4 weeks. That way you will have many different herbs growing at different stages. You will find that you have a constant source of fresh herbs year-round.

12. Buying the same seeds and same varieties

Having too much of one particular type of herb can become a little boring. And you may run out of ideas on how to create different dishes or beverages using the same herb all the time. 

Instead, try different varieties of the same herb (for example common basil, Thai basil and cinnamon basil) or buy different herbs. 

You may be surprised at just how many types of seeds are available for herbs you may never have heard of before – and certainly herbs that may not be available in your local market.

13. Buying seeds for the wrong reasons

To grow herbs from seeds does require some level of attention to detail and a bit of your your time. 

Unless you are willing to:

  • Invest your time in the growing process
  • Look after your plants
  • Use your herbs in your kitchen for dishes or beverages

Then there is little point in spending money on seeds. I have seen friends who just want to fill pots with fragrant kitchen herbs but are unwilling to care for them, let alone use them. 

You will end up with a sad, wilted collection of neglected pots that you are removing from your window sill.

Meet the author: Mattias is an experienced gardener spending most of his free time on his knees among herbs, plants and garden vegetables. For the past two years he has been sharing gardening projects and how-to tutorials on the NordicLavender website and YouTube channel.