BBC HomeExplore the BBC
This page was last updated in May 2008We've left it here for reference.More information

22 July 2014
Accessibility help
Text only

BBC Homepage

Local BBC Sites

Neighbouring Sites

Related BBC Sites


Contact Us

Like this page?
Send it to a friend!

 

Features

You are in: Lancashire > Nature > Features > Ask the gardener: Onions and olives

Onion

Ask the gardener: Onions and olives

How to care for your onions and olives...

Warton's Bill Blackledge is one of the county's most popular and sought after gardeners.   If it's green and needs watering, Bill can tell you about it.  He has been answering BBC Radio Lancashire listeners' queries for over thirty years, which means he's been there nearly as long as the transmitter!

His knowledge is encyclopedic. After training at the under the then Ministry of Agriculture, Bill spent over twenty years at the Department of Biological and Environmental Services at Lancaster University.  Now, he's a regular course tutor at Alston Hall, Longridge and Lancaster Adult College.

For three decades, Bill has travelled the county with fellow judges as a regional judge for North West in Bloom.

So, whatever the problem, we like to think Bill can sort it out... at least that's the theory!

--------------------

ONIONS

--------------------

Paul Bleasdale asks...

Could you tell me the best time to plant onion sets and shallots in Burnley?

Bill replies...

Both onion and shallots need to be planted Paul in a well drained soil, they will not tolerate very wet and damp conditions.  I would wait until your soil has dried out and, again, depending on weather conditions I would plant your onion/shallot sets towards the end of March.  Before planting I would work into the soil a general base fertiliser - such as Fish Blood and Bone Meal - which will give your plants an added boost.

------

Jed asks...

Can I grow onions in containers?

Bill replies...

Yes onions can be successfully grown in containers. You would be better using a soil based compost (Jon Innes No 2) and a fifteen inch deep container  - you will be able to grow six decent onions. Good varities are: Hysan and Red Barron. You will need to keep your plants well watered and fed regularly. If you wish to grow the salad spring onions these can be easily grown in window boxes and shallow containers.

------

Alan Hirst asks...

If I manure my onion bed every autumn, am I doing right in liming the bed every February?

Bill replies...

Onions prefer a well drained and well manured soil.  Manuring in the Autumn - which you are doing - is the ideal time. On the question of liming your soil I feel it is worth while to check whether your soil is acid or alkaline (easy to use ph indicator kits can be obtained from garden centres) and this will ascertain whether your soil is acid or alkaline (limey)

Onions do not like acid soil and, if you find that your soil is on the acid side - applying lime to your bed - as you suggest in February - is the ideal time.

------

Chris asks...

When onions start to seed, do I take off just the seed head or the whole stalk? Thanks

Bill replies...

Due to the very high temperatures quite a number of onions are starting to seed and there are contrasting views Chris on what to do with the onion stalks.  Some allotment holders just take the seed head off - others just bend over the top part of the stalk and the eminent onion grower Margaret Robinson takes the whole stalk off at base level.  Once your onion has started to seed it will virtually have finished growing and you can gently fork the onion out of the ground and place it on its side to dry off.

--------------------

OLIVES

--------------------

Gilly asks...

When and how should I prune back an olive tree growing in a pot?

Bill replies...

Olive Trees are becoming a popular plant Gilly but they do require a well drained growing medium and with your Olive growing in a large pot you will need to feed regularly with a balanced fertiliser during the growing season.  With regard to pruning very little pruning is required but, if your plant is growing too large you can trim back the shoots just above a leaf joint and this needs to be carried out in the spring

------

Richard Young asks...

Last October I brought back 3 olives from my honeymoon in Morocco, planted them together in a large pot with lots of peat compost and promptly forgot about them, until early this year when lo and behold 3 small leaves were poking out. I have repotted them a couple of times during their growth and now have my smallest in a pot 5 1/2 inches diameter the largest in 8" diam. They have been kept indoors as the weather has been miserable and are in a window where they get strong light most of the day. I water regularly and feed them when I can remember every 3-4 weeks with baby bio.
What I was wondering is if I need to do anything to help them grow into trees? And should i put them outside if we ever get a proper summer as well?

Bill replies...

It is important with your Olive seedlings Richard to ensure they receive maximum light intensity as this will stop them etiolating/going leggy and, if we do have some reasonable weather in the coming three months I would place your plants outside in a sheltered but south facing aspect as this will harden the small plants off but, with the plants being so small I am afraid that you are going to have to keep them indoors during the winter months.  They do however need to be kept very cool and on the dry side and in a very light position.  It is also important to protect your plants outside from slugs and snails.

------

Theresa Goss asks...

I have had an Olive tree in a wooden tub/barrel, outside, for nearly six years and it has grown well up until now. Most of the leaves have dried up and fallen off and I am afraid I have killed it; a) because I moved it from a sunny to a not so sunny spot b) I have planted bulbs (Cheerfullness Daffs) around it or C) and the most likely cause - waterlogged it. Is there any way I can resurrect it?

Bill replies...

Olive Trees love to be planted in a well drained soil Theresa and as you suggest if your soil is waterlogged this is the most likely reason for the leaves of your Olive Tree to have fallen off.  It could also quite easily have been caused by frost damage.  If the shoots on your Olive Tree are still green there is a good chance that new leaves will appear but it is very important that you ensure that your Olive Tree is growing in a sheltered sunny position and also is a well drained soil.

------

Pauline Humphreys asks...

I would like to know the best way to plant my olive tree into a terracotta container. Should I line the container? I have some sterilized top soil? It's in the conservatory. It's about 6ft high. Should the leaves be falling off? Some of the leaves are sticky.

Bill replies...

There will be no need to line your terracotta container if it is made of clay Pauline and if you intend to use sterile soil for repotting your Olive tree you will need to mix the soil with peat and a sharp grit sand.  Olive trees love a well drained potting medium and | would recommend using a mixture of two parts sterile soil, one part peat and one part grit sand and you will also need to add a small amount of a base fertiliser and a sprinkling of ground lime stone.  Regarding some of the Olive leaves feeling sticky I would check for aphids - the sticky substance I am sure is the honey dew secreted by the aphids. 

------

Jackie asks...

I have an olive plant in a tub which was outside during the summer, I have now put it into a relatively cool unoccupied bed room. The leaves are dropping off. Should I be watering it? And do you think it's in the right environment?

Bill replies...

Olive plants are becoming very popular now Jackie, they are an evergreen plant and unless your garden is very sheltered you will need to keep your plant in a cool greenhouse or light porch, and one of the reasons why the leaves are dropping off your plant could be the very dry atmosphere in your bedroom even though, you say it is a very cool room - on sunny days the temperature could be quite high.  Olives are an evergreen plant and you will need to give them water over the winter months but not vast amounts.  As soon as the weather improves I would place your plant outside.

------

Francis Dalli asks...

I have an olive tree growing in a large pot which is now about 8ft tall. I water and feed it regularly perhaps even too enthusiastically. I have enjoyed its big fruit (table type) for three years. Now I notice that it is rapidly losing its vigour and this year has not produced any fruit. The bark has split up vertically at different places almost all around the trunk, at the level of the soil. Is there a way I can save the tree? My friend suspects that I have watered and fed it too generously. Any advice would be greatly appreciated.

Bill replies...

During the growing season Francis you will need to keep your Olive Tree moist but not over watered and you will only need to feed your plant approximately once per month and I would use a balanced liquid fertiliser. Olives do not like too rich a compost and during the winter months you need to keep your tree slightly on the dry side and, unless your garden is very sheltered during the winter period it would be far better placing your tree in a cold greenhouse or light porch.  Olives do need a cold period during the winter to initiate flowering.  I tend to agree with your friend Francis that you have been giving your tree to much feed and water and the splitting of the bark could have been caused by frost or too lush growth by overfeeding.

------

Susan Law asks...

I have an olive plant, approximately 4ft tall, which lives in the conservatory and has started bearing tiny buds/flowers. It is in a 6in pot. Should I repot it now? Help.

Bill replies...

If your plant is pot bound I would repot your Olive into a 10" terracotta pot ensuring that there is plenty of drainage in the bottom and I would use a soil based compost - John Innes No 2 or 3.

It is very important when repotting your plant not to damage or disturb the roots as this could affect the flowering of your Olive plant.  Olive plants are ideal for a conservatory - they will tolerate cool conditions in the winter months and the very hot dry conditions during the summer months.   Throughout the summer months you will need to ensure your plant is well watered and feed with a general liquid tree fertiliser.

------

David asks...

I have purchased a small olive tree and would like to plant it in my south facing garden could you please give me some advice on planting and caring for olly? Many thanks

Bill replies...

Your Olive tree David needs to be planted in a rich loamy but well-drained soil.  They cannot tolerate waterlogged conditions, especially during the winter months.  A south facing garden is ideal but, you may still need to protect your tree during severe winters.  This can be done by using white fleece.  If you feel that you do not want to take this risk Olive Trees are quite happy growing in large containers which can be moved to a sheltered spot during severe weather conditions.   If grown in containers you will need to water and feed on a regular basis

------

Lai Chee Woon asks...

I have purchase a small Olive tree (12 ins tall) a few weeks ago.  It needs repotting. It is currently in a 6 ins pot.  What type of compost does it require and what size pot is best for repotting.  It has lost quite a lot of leaves since I bought it as my balcony gets a lot of sun and it did dry out completely.  It has a lot of flowers on it.

Bill replies...

I would re-pot your Olive Tree La into a ten to twelve inch pot and I would use a soil based compost such as John Innes No 2 or No 3.  Olive tree love a well drained compost and to the John Innes compost I would also add approximately 10-15% sharp grit sand.  Keep your plant well watered especially during the summer months and I am sure your Olive Tree will recover from drying out.

NB: During the winter months Lai it is important that you do not over-water your Olive Tree - they need to be kept slightly on the dry side.

------

Louise Toy asks...

We have a beautiful 7ft plus olive tree which until very recently looked very healthy. It is situation in a small walled garden in a sunny position. In the last few weeks a number of leaves have started turning yellow and are now beginning to fall off.
Could this be through lack of watering or could it be the result of my husband pouring washing up water (complete with washing up liquid!) onto the plant?

Bill replies...

Your Olive Tree is ideally situated in a South facing garden Louise and also in a sheltered position but, if your tree has been suffering from drought conditions there will be a tendency for the leaves to yellow and drop off.  It may however be worthwhile to give your tree a boost by top dressing with a general based fertiliser such as Fish Blood and Bone Meal or Vitax Q4.  And, after a heavy rain fall - if at all possible - it would be  worthwhile to mulch around your tree with some well rotted manure.  This will not only add nutrients to your tree but will also retain the moisture.

On the question of your husband pouring washing-up water onto your tree if the washing up liquid is highly concentrated it could cause problems and it is always advisable to use bio-friendly products!

------

Shana asks...

I recently planted an olive seed. I used john innes loam based compost for seedlings. I also cover the top of the pot with a plastic sheet to help with the germination of the seed. Firstly, have I used the right compost? Secondly, am I supposed to keep it near a slight heat source and cover the top of the pot with a plastic sheet to help with the germination and thirdly, how long will it take to sprout?

Bill replies...

If your John Innes compost is the seed compost it will be fine for your Olive seeds to germinate in.  You will need to keep the seeds moist and will need to be kept in a temperature of approximately 20 degrees centigrade.  As soon as the seeds have germinated Shana and are large enough to handle they will need to be pricked out into three inch pots.  Again you can use your seed compost and they will need to be placed in a light position in a temperature of approximately 10 degrees centigrade.

------

John Lipscomb asks...

I had an olive tree in my greenhouse which became diseased last year with a black sticky substance and there were very small black beetles motionless on the stems and leaves.  I removed it from the greenhouse but now 4 months on my lemon tree in the same greenhouse is suffering from the same disease.  Do you have any idea what the problem could be and is there anything I can do to cure the problem to stop it spreading to my other trees in the greenhouse?

Bill replies...

The black sticky substance on the leaves of your Olive Tree John is, I am sure, sooty mould which is a mould that survives and grows on the sugary glucose which has been secreted by aphids and also scale insects and, what you will need to do is with warm soapy water wash this sticky substance off the leaves.  You will also need to look closely on the under side of the leaves of your Olive and Lemon Trees to see if there are any small scale insects present.  If there are scale insects present you will need to spray with an insecticide but, if you are going to use the Olive and Lemon fruits you will only be able to use a contact safer insecticide. If you have no intention of using the fruits you could use a systemic insecticide which would be far more affective.  With regard to the black beetles which stay motionless on the stems and leaves these could quite easily be Black Vine Weevil adults and you will need to remove these from tree and you will also need to check your soil to see if there are any white pinkish grubs as these are the grubs of the Vine Weevil and will eat the roots of your trees.  There are websites available with more detailed advice/photographs on Vine Weevil.  If you feel you do have problems with Vine Weevil please email BBC Radio Lancashire again I would will give you further advice.

------

Bec Malone asks...

I have an 8/9 foot olive tree which was repotted into a 20 inch pot a year or so ago. It's suffering a lot at the moment as lots of the leaves on the lower branches have fallen off, and it really is beginning to look quite sparse. It looks root bound at the top, but there are no roots pushing their way through at the base. I water it well during the growing season, tending to water only a little during winter. It's currently on our patio in a sheltered position and we have a south facing garden. Would you advise repotting it again? if so what size? I would also be grateful for any advice with re. soil (peat or soil based?) and feed.

Bill replies...

Early springtime Bec you need to remove your Olive Tree from its pot to see if it is completely pot bound.  If this is the case it will be worthwhile to repot into a larger container.  The compost I would use is a soil base compost John Innes No 2 or 3 and I would add to the compost a fifteen to twenty per cent sharp grit sand.  Olive Trees love to be repotted into a soil based but well drained compost and, during the summer months you will again need to feed with a general base fertiliser.  If however your tree is not pot bound it is still important to feed your Olive Tree regularly during the summer months.

last updated: 01/05/2008 at 09:19
created: 20/10/2006

You are in: Lancashire > Nature > Features > Ask the gardener: Onions and olives



About the BBC | Help | Terms of Use | Privacy & Cookies Policy