Hardening off and potting on – an easy guide to gardening terms

JoHome & Garden, Lifestyle

Yellow primrose in a border after hardening off

Hardening off and potting on are gardening terms you are likely to hear a lot of, especially at this time of year when people across the country are preparing outdoor spaces for the season ahead. What are they though, and why should you take note? I’ve compiled a guide to some of the most common gardening terms to help you find success with your plant life.

Potting on a shrub


This is when plants, especially young shoots, are covered to restrict the light available to them. This keeps them pale in colour, and in many cases makes their taste more tender. It’s common when growing vegetables such as celery and rhubarb.


I experienced a lot of this last year when a sudden heatwave arrived whilst we were on holiday and not tending to our plants! Bolting (or describing a plant as having bolted) is when the plant grows very quickly. Sometimes it might flower before you would like it to as well. It is almost always caused by some sort of external stressor, such as significant temperature changes or drought.


You may also hear this referred to as tilling. It is digging into your soil to prepare it for new plants. Whilst farm fields would be prepared with machinery, your borders or beds are best tended to by hand. I use a hand fork and trowel to dig into and turn over my soil before adding new plants.

Earthing up

This is the practice of piling earth around a plant. It common to use this gardening term when referring to growing root vegetables such as potatoes. You add earth or compost as new shoots appear so that when you come to harvest the crop they are edible. You can also do this with carrots to prevent green tops. It may help to keep the flies off the vegetables as well.

Green manure

This is not quite what it might sound like! Green manure is a fast growing ground plant that is used to cover bare soil. They are often used in vegetable patches to prevent growth of plants that you might wish to deter. I would choose to use clover as green manure. Both red and white varieties are perfect for this job, grow quickly and look very pleasant.  

Hardening off

People often start growing fruit and vegetable plants in the early months of the year when it is too cold to grow directly in the ground. Instead you will find trays of young plants filling greenhouse shelves and windowsills around the country. Hardening off is one of the gardening terms used to describe acclimatising these plants to outdoor living conditions. I tend to grow my seedlings on a sunny windowsill. When it comes to hardening them off I pop them outside for a few hours each day over two or three weeks before planting them out. You still need to be mindful of overnight frosts though. If you move them fully outside before the last of the frosts make sure that you have some fleecy blankets or thick towels to wrap them up again overnight if needed!


Many of us will have learnt about crop rotation during school geography lessons, but the term intercrops is not so often heard. This is when two (or more) crops are grown in the same space, so that you can look after multiple plants at the same time. This ensures a good crop of plants throughout the year, and uses less space so really makes your borders and beds work hard for you. Examples include placing fast growing plants such as chard or spinach next to slower taller plants such as sweetcorn.

Lawn aeration

Early spring is an ideal time to aerate your lawn. Using a fork, prick holes into your lawn to allow additional oxygen into the ground which encourages root growth. This process also enables additional nutrients to enter the ground, along with water, keeping your lawn fresh and healthy. If you miss your chance in the spring, you can successfully aerate in the autumn too.

Mulch (also known as leaf mould)

As leaves break down they release valuable nutrients which can be hugely beneficial to plant life. Rather than leaving my entire garden covered in fallen leaves, I collect mine up and put them in a container. During the spring I then use the resulting mulch as a sort of top layer of compost to insulate and enrich the soil. I normally do this during the cultivation process (see above) or when refreshing my pots (see below).

Plant pots for potting on

Potting on

If plants are being grown in a pot, whether on a temporary or permanent basis, there is a risk that they can become root bound. This is when they run out of growing space in their container. Potting on is the gardening term used when you move them up to a bigger pot. This is very common when you are growing fruit and vegetable plants. For example I start mine off in a small propagator, then slowly move them up through two larger sized pots before hardening them off and planting out. If you aren’t going to plant directly into the soil, I would recommend changing the pots every two years. This ensures that roots have space to absorb the nutrients and water that they need for the plant’s growth.

Pricking out

This is much the same as potting on, but is when you take the seedlings out of a tray or propagator. Make sure they have at least two sets of leaves before pricking out. The seedlings are often so delicate that you can’t easily do this with your fingers alone. If you are gentle, you can use a pencil or invest in a special pricking out tool whilst carefully holding the top part of the plant. If you don’t do this, there is a higher chance that some plants will die due to damp or overcrowding.


The final of my gardening terms in this post is transplanting. This is when you move a plant from one place to another. It may need transplanting because it needs to have more or less light or space than it is getting in its current location. I have done this recently with a tree that we needed to move further away from our house. We carefully dug a large hole around it to uncover the roots and very gently remove them without damage. If you are moving a tree or a shrub, remember to water it well in its new position. Don’t use a sprinkler if at all possible as this encourages roots to establish themselves closer to the surface of the ground. Instead you want them to dig deep. Then, in harsher weather conditions such as the heat of the summer they can draw the water and nutrients that they need to enable the plant to continue with its growth.

Delicate cosmos flowers


I hope that you have found this introduction to gardening terms useful. Wishing you happy gardening!

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