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Borage – How To Sow, Grow And Harvest

Borage is a secret favourite of our herb garden. We love the gorgeous star shaped flowers and feathery foliage. The bees can’t get enough of them either!

  1. The seeds can be started off indoors and under cover 3-4 weeks before the last frost. You will need to keep an eye on them as they don’t need to have too long indoors before they are strong enough to be handled.
Borage seeds are quite large for a self seeding herb
Borage seeds are quite large for a self seeding herb
  1. Make sure to use a compost that is peat free but also full of organic material. If you are planting straight outside dig some homemade compost through. The seeds will need to be planted thinly with about half an inch of soil to cover them. As they are quite large it is easy to get them clumping together, 2-3 together is not the end of the world when putting into the ground, but I would avoid it.
  2. If they are planted indoors it really is very quick and you will find that they get overcrowded very easily. So about 3 weeks after sowing you will be ready to plant them out. Borage grows a very long tap root and this is where the overcrowding comes in.
Borage has a very short germination time and is really vigorous once it has started.
Borage has a very short germination time and is really vigorous once it has started. This photo was taken at around day 7 after sowing
  1. Lift the young seedlings out of the planter – if you like you can start each individual seed off in a biodegradable plant pot. That way the roots are not disturbed at all. I use a dibber to make the holes in the soil where they are going to be planted. This is because I want to leave enough space for that long tap root. Your plants will grow to as large as 12 inches wide if you pinch them out so I tend to leave around a foot between each plant.
  2. If you have planted directly to the ground, now will be a good time to thin them out further. Try to keep that great long root whole and move them on gently. Borage is not a massive fan of being transplanted, so it does work well to start them off in pots that can them be moved into the ground and allow the roots to still break free!
  3. About ten weeks from sowing they will be ready to harvest the leaves. Borage leaves taste like cucumber and therefore make for a rather unique taste in salads. Especially alongside the radiant flowers.
This young borage plant is about 3 weeks old and has a very long tap root already.
This young borage plant is about 3 weeks old and has a very long tap root already.

You can harvest the leaves from about week 10 but the flowers will take a little longer.

Use the leaves in cordials and salads, or even cocktails as an interesting sprig of colour and refreshing taste. The flowers are also perfect in salads and offer a shot of colour to any ice cube that you may want to add to a jug of Summer Pimms.

To buy your seeds for your first crop check out the James Wong Developed Borage Seeds from Suttons. We use these and they last a long time. So a packet can go a long way. We also like the germination rate on them. I like to give herbs as gifts and realistically borage will take 3-4 weeks to get to a size that they can then be planted on. This means that you don’t have to look after the seedlings for long before swapping them with your neighbor!

In year two, however you may chose to let your borage become compost before it seeds – that way you can move it around the garden.

How To Collect Seeds

Borage will self seed. This means that ours creates it’s own display throughout the year. We also grow is as green manure and will avoid it self seeding at all costs.

The seeds develop once the flowers have started to die back and you can cut the heads off once you see seeds. To save them just hang the boughs upside down with a paper bag underneath. This will catch the seeds as they ripen and fall off naturally. Sometimes a little tap will help to loosen them!

This can be a nifty balancing act as you may not want to grow borage in the same spot each year, but equally you very much do want the purple/blue starry flowers to open up! So keep an eye open and nip out any flowering stem that has started to go over. Add it to the compost bin straightaway and water it down. That way it should avoid seeds developing.

Borage As The Perfect Green Manure

If you sow your borage seeds after the last frost you will get a fantastic array of Summer flowers from June to July. Spacing planting by 4 weeks allows for an even longer period. However the wonderful properties of borage mean that it can be sown later in Autumn and provided there is a degree of protections against frost provided it will grow overwinter and provide perfect ground cover.

A green manure is a plant or herb that can be grown to provide a number of benefits for your garden.

Firstly ground cover, this ground cover deters garden weeds from growing. Mainly because the green manure is so thickly covering the earth that no sunlight can get through. If planted in Autumn borage can provide this in time for you to leave your garden until the following year.

Secondly to pull nutrients from the ground and convert them into user friendly nitrogen. What this means is that some of the plants we choose to grow do not have the innate ability to use nitrogen that is stored in the soil. It needs to sort of be processed into a more easily absorbed form. Borage is one of those herbs that can take the nitrogen and potassium from the soil and convert it into its more usable form.

The even better property of borage is that long tap root we mentioned earlier. This means that nutrients all the way deep down, passed most plants root systems, can be brought up and stored in the plant.

To release all of that wonderful goodness, you can wait until after the flowers have started to die back but not wait as long as for the seeds to start to form! Then you cut the plant back to the ground. The leaves can stay on top of the surface for a day or two, we let our chickens free range at this point to kill off any slugs and snails that have made the leaves their homes. Then we dig the wilted leaves into the soil. By using a sharp spade we can ensure to chop the leaves and stalks further as we dig it through.

Two weeks later and the patch will be ready to grow new vegetables on again. You will not need to buy any compost or move anything from the heap at the top of the garden to the bed. This is perfect lazy organic gardening and proves that organic gardening can be cheaper than chemical shop bought stuff.

Borage Makes Amazing Liquid Fertiliser

Due to that amazing property of pulling nitrogen and potassium out of the depths of the soil, borage will be packed with the stuff. So we can sling it on the compost heap, or cut back and use it as green manure. Or we can chuck it into an old coffee sack and lower into a large bucket of water.

You will need to chop it down first. Getting as much juice out of the stems as possible. Then put it into the hessian sack and tie together with garden twine. Leave the twine hanging over the edge so that you can remove the sack when you are ready. Cover with water and pop a lid on.


You may want to sort of stir it around a few times, but 4-6 weeks later you will have the stinkiest quality liquid fertiliser on earth. You can then still chuck the rest of the hessian sacks contents to the compost heap and that way nothing goes to waste.

Dilute the fertiliser by about 1/4 to water. Then add to your watering can and water to the bottom of any plant you want to feed. Dill will appreciate a good feed a few times a week in drier weather. Your bay tree is another herb that will thank you for a feed. But do not get any on the leaves as it can cause a burning effect.

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History and Medicinal Uses Of Borage

Borage is native to the Mediterranean and as such has a history that matches that of the Ancient Greek and Roman Empire. Borage is associated from those times with courage and bravery being used to flavour wines drank in ceremonies before battle. We can now use to flavour herbal teas, although I’m not sure on how brave that makes me.

Borage seed oil is now commonly used as an anti-inflammatory and taken orally in capsule form. As far back as Ancient Greece it was used more to ease melancholy and relive a depressed heart.

Whether these properties are true has not had too much research and it is always advised to take supplementary herbal medicines after seeking professional advice from a medical practitioner.

We know that borage is a tasty addition to many salads and will form part of a happy country garden.

If you are a bee keeper you will be able to attest to the positive effect that borage has on the flavour of any honey that your hive produce. It will be the best companion plant as it attracts so many pollinators to the garden.

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