HOW TO GROW BULBS.
Updated: Aug 13, 2021
Everything you need to know to grow dazzling daffodils and other beautiful bulbs.
So what exactly is a bulb?
Cut into an onion and you will instantly see what most bulbs look like inside. Bulbs are underground storage organs composed of fleshy scale leaves or leaf bases. This structure has evolved to allow them to survive inhospitable climactic conditions such as heat, drought and cold.
The good news is that most of those stars of spring, including daffodils and tulips, already have a fully-formed, embryonic flower inside the bulb. For those of you gardening in warmer climates, Freesia, Sparaxis and Scilla are in the same category. This means that with the right temperature, water and a little sunlight, success is (almost) guaranteed.
To listen to our podcast about bulbs, click here.
When is a bulb not a bulb?
Often sold at the same time as bulbs, corms, tubers and rhizomes have all evolved, just like bulbs, to survive in climates that have periods of less than ideal conditions for optimal growth. They are categorised differently as they have a structure that diverges in shape, growing points and also the ability to divide and increase. Crocus are an example of a corm, Iris have rhizomes (a modified plant stem), and possibly the most beautiful plant to have a tuber is the tuberous Begonia. Oh, did I mention the potato? It is a tuber too and possibly the most well-known of this group.
Is your climate right?
Classic spring-flowering bulbs such as tulips, daffodils, hyacinths require a cool climate, that is if you get a regualar frost in winter, then you are good to plant these bulbs.
Those in temperate to sub-tropical climates may be able to grow tulips and hyacinths if the bulbs are chilled in the crisper section of the fridge before planting (it has to be the crisper section otherwise you might kill your bulbs!).
But never fear, you can still plant some bulbs in warmer climes. Bulbs that thrive with a bit of heat are Freesias, Sparaxis, Ixia, hippeastrum.
My first attempt at growing daffodils was, frankly, disastrous. I bought a packet of bulbs that I failed to check before purchasing. Yes, please feel free to, lightly(!), squeeze those bulbs to check that they are firm and not rotting before purchase. I did not.
Secondly, there should be very few obvious blemishes on the bulb and no cuts into the bulb.
Thirdly, buy from a reputable supplier that replenishes their stock each year.
By all means shop locally, but wisely! You should start seeing spring-flowering bulbs in your local nursery from early autumn.
If the internet is your marketplace, you will be able to buy bulbs online from late summer and suppliers will mail out the bulbs in early to late Autumn. Of course, you can still get a catalogue in the mail and order via snail mail. We suggest purchasing a limited number of bulbs first from a new supplier to check their quality.
When and how to plant bulbs
Timing is vital
It is vital to plant at the right time of year. Spring flowering bulbs should be planted in most areas by mid-autumn and summer flowering by late winter to mid spring.
Some liberties may be taken with this (Clare planted her first season of bulbs in late autumn) but the bulbs may not flower to their full potential as the roots won’t have time to develop. If you have listened to our podcast, you will know the importance of roots!
Let there be light!
We know this sounds obvious, but all plants need light and most bulbs require at least three to four hours of sun daily. More sunlight is generally preferable.
My daffodils were not only rotting, but I planted them under a tree that had annexed all of the soil with feeder roots and ensured that the sunlight that reached ground level was pathetic.
Some bulbs will grow underneath deciduous trees, but in climates where the spring is short, we recommend bulbs that flower during winter or earliest spring as they are able to take advantage of the light before the tree leaves emerge and expand. In this position it is vitally important that the soil is amended with organic matter.
Prepare your soil!
Tend to your soil a few weeks before planting and dig in some form of compost or organic matter. No fresh manure please, aged or decomposed is absolutely fine. We also add a balanced general fertiliser which can be organically based if you wish.
Bulbs are fantastic seasonal potted plants and will thrive in a quality potting mix or potting compost. Most bulbs can thrive in a container year after year, but it is a good idea to replenish the potting mix and fertilise properly.
When bulbs emerge, a light top-dressing of the same fertiliser could be used, or a balanced general liquid plant food at regular intervals.
How low do I go?
Planting at the right depth is also rather important as in border-line climates planting, for example, tulips and daffodils too shallowly can result in the flower aborting.
Plant to a depth of approximately two and a half times the height of the bulb, which often means that tulips and daffodils must be plunged to between 10 and 30cm!
Two’s company, three’s…
In this instance three is definitely not a crowd! Grouping bulbs allows for pleasing colour associations to occur.
Just make sure that the bulbs flower at the same time and have complimentary heights.
Think of the direction from which you will view your gorgeous display. Starting initially with the lowest growing bulbs in front is helpful and if you require a succession of flowers, plan accordingly. As experience is gained, bend the rules!
Water, water, everywhere…
And lastly, water, water, water.
Never allow bulbs in containers to dry out. The mix should be just moist at all times.
In the garden, if no rain has fallen for a fortnight and depending on temperature, watering thoroughly is advisable.
When the soil appears dry on the surface, check with your index finger, and if it feels dry, water! For those gardening in climates where the soil freezes during winter, take a break! No watering will be required, but planting must be done at least one if not two months before the big freeze to enable the bulb roots to start growing.
After the party’s over
Sometimes the party’s not. Choose the right varieties for your climate and conditions and your floral friends will be returning to delight and inspire for years.
Oh, and adhere to the fertilising suggestions above and your bulbs will be able to concentrate on building reserves to double or treble your display the following year!
Top Tip: After the party is over for your daffodils, do not touch them. You must let the foliage wither and brown otherwise they will not flower the next season. And that would be sad.
My first attempt at growing daffodils all those years ago might have been a failure, but I loved them so very much I redoubled my efforts. Now every spring daffodils and numerous other flowering bulbs in all shapes, sizes and colours, grace my garden and I am very pleased to say, Clare’s garden too.
Give bulbs a go! You will not be disappointed!
Colan’s favourite bulbs
Dwarf daffodils and jonquils
Tuberous Begonia (not technically a bulb, I know, but I adore them)
Clare’s favourite bulbs
Monet tulips (single late tulips)
Hoop petticoat daffodils
To listen to our podcast about bulbs, click here.