vegetable growing techniques
Carrots are fairly easy to grow but gardeners can run into difficulties when the seeds are germinating and the young seedlings are in the early stages of growth.  Below are some hints to help you grow good carrots.
To do well carrots need:-
  • Light well drained soils.
  • Slightly acid soils.
    Though they will tolerate a relatively wide Ph range (5.5 to 7.0).
  • Seeds need 12+ degrees soil temperature to germinate.
  • Even soil moisture levels.
    When the seedlings are very young, from just emerging to two centimetres high.
  • Even soil temperatures.
    When seeds are germinating.
  • Protection from slugs and snails.
    Though generally only in the early stages, once the carrots are larger than five to seven centimetres they are usually pretty safe.
preparing the bed
Photo of carrot bed.
preparing the soil
The soil needs to be light and friable and well drained.  If you have heavy soil add up to a shovelful of sand per square metre to make the soil  more friable.  Builder’s sand (children's sandpit sand) is ideal, though you can also use coarser sand.  A shovelful of compost can also be added as long as it is well broken down, no large lumps.

Raised beds are ideal for growing carrots because they have better drainage than a standard vegetable bed. 

adding fertiliser
Carrots do not need much fertiliser. To fertilise the bed spread a handful of blood and bone per square metre. 

You can add small amounts of animal manure but be aware that this will increase the likelihood of split roots, so generally it is not recommended.  You can also add half the recommended dose per square metre of NKP fertiliser.  If your soil is in good condition you can plant into it without adding fertiliser at all and top up with a little bit of liquid fertiliser when the carrots are bigger.

Turn the sand, fertiliser, compost and soil in until its consistency is even then rake flat.   

when to plant
Carrot seeds require soil temperatures of 12+ degrees to germinate properly.  Seeds planted into cold soil are less likely to germinate and the growth rate of any seedlings that do come up will be slow, prolonging the vulnerable small seedling period when the risk of damage from snails and slugs is greatest.

While you can use a soil thermomotor to check soil temperature the best indicator that the soil is warm enough to plant carrots is when the lawn begins to grow vigorously.  This will very depending on the climate in your area, in Ballarat (where I live) lawn usually begins to grow vigorously in early to mid October. 

Of course you can put in later plantings of carrots as the season progresses but the earliest you can plant reliably is when the lawn begins to grow vigorously.

For more information on when to plant carrots in your area click HERE to down monthly seed planting guides for South Eastern Australia.  These guides cover three zones:-
    Ballarat District, includes the townships of Ballarat, Ballan, Meredith, Skipton, Beaufort, Clunes, Creswick and Daylesford.
    All of Tasmania and the cool mountainous areas on the mainland from Just West of Ararat to the North of Canberra.
    Coastal: South Eastern SA, coastal Victoria and coastal NSW up to Sydney.  Warm inland: Just North (Victoria) and West (NSW) of the great dividing range, including the cities of Bendigo and Albury. 
Note that these guides do not cover Queensland, Western Australia, most of New South wales and South Australian and the North West part of Victoria.
preparing a carrot seed raising mix
Carrot seeds can be sown directly into the soil but you will get a better germination rate if they are planted into a seed raising mix.   You can use a standard commercial seed raising mix but I prefer to make up a lighter more sandy mix.  Below are two specialist carrot seed raising mixes that I use:-

  1. Mix 50% sieved compost with 50% fine sand.
    This mixture can be varied with fine coconut fibre and vermiculite. 
  2. Mix 60% commercial seed raising mix with 40% fine sand.
You can in fact use any number of combinations but whatever you end up with it should be at least as friable as a commercial seed raising mix.

planting a carrot bed
There are two planting methods that I use to grow carrots:-

traditional planting method
This method produces the biggest carrots but involves more thinning of seedlings.
  • Create small furrows 1cm deep and 20cm apart.
  • Add 1/2 to 3/4 centimetre of the seed raising mix to the furrow.
  • Sprinkle the seeds evenly on top of the seed raising mix aiming for two to three seeds per centimetre of furrow. 
    If you add more seeds the bed will need too much thinning, add fewer seeds and you may end up with bare patches.
  • Cover the seeds with another 1/4 to 1/2 centimetre of seed raising mix and lightly water in.
  • When the seedlings are about three centimetres high thin to five centimetres apart.
    Place some of the thinnings on their sides next to the rows to act as decoys for slugs and snails.
  • When the seedlings are around ten centimetres high thin to ten to fifteen centimetres apart.
  • The bed should be regularly weeded, especially in the early stages.
  • Mulch can be added between the rows but only after the carrots have reached a height of at least 12 centimetres.

dominant carrot planting method
This method produces carrots that are generally a little smaller than ones grown using the traditional planting method but a dominant carrot planted  bed will produce more weight of carrots per square metre of soil than than a bed planted using the traditional method and requires less thinning.
  1. Create furrows 1 cm deep and 3 to 5 cm wide in rows 25 cm apart.
  2. Spread 1/2 to 3/4 centimetre of seed raising mix over each furrow.
  3. Sprinkle seeds along each furrow so that the length and width (3 to 5 cm wide) is covered with two to three seeds per square centimetre.
  4. Cover with 1/4 to 1/2 centimetre of seed raising mix.

  5. Only thin out if there are very thick patches of carrot seedlings.
  6. As the carrots grow to full size you will notice larger carrots that are dominating the others, these are the ones that you harvest first. 
    By picking the largest carrots you free up space for smaller nearby carrots to grow bigger.  Keep picking the larger carrots until there are only weak straggler carrots left then clear the bed completely.
  7. Weed and mulch as for the traditional planting method.
covering young carrots
Given the right climate conditions carrots will germinate and grow in the open but they will do better if they are covered in the early stages of their growth as this offers better moisture and temperature control.  It also reduces the risk of damage from slugs and snails.

traditional covering methods
  1. After planting the seeds cover each row with planks of wood or the entire bed with an old sheet or towel.   
  2. After about a week check each day to see if the carrot seeds are pushing through the soil.  Once they are clearly showing then remove the planks or sheets.
The main disadvantage of these covering methods is that you cannot see the emerging carrots unless you lift up the planks or sheet,  if you forget to check then eventually the seedlings will be damaged due to lack of space and sunlight.

shadecloth method
Illustration 1 of planting carrots using polypipe sticks and shadecloth.
Lay polypipe sticks across the rows of planted carrot seeds, cover with 50% shadecloth and pin the sides.

Illustration 2 of planting carrots using polypipe sticks and shadecloth
When the carrot seedlings are pushing up against the shadecloth remove both the shadecloth and polypipe sticks.
  1. After planting the seeds place lengths of 13 or 19mm polypipe on top of the bed at regular intervals.
    These are there to keep the shadecloth slightly off the ground. Pieces of wood or old garden hose can also be used. 
  2. Cover with a length of 50% shadecloth. 
    75% shadecloth can also be used but I have found 50% shadecloth to be better for vegetable gardening purposes. 
  3. Pin the edges of the shadecloth with bird netting pins so that the cloth is stretched tightly over the polypipe sticks.
    Lengths of wood or star pickets can also be used to pin the shadecloth down.  If there are lots of slugs and snails around then bury the edges of the shadecloth in the soil so that the emerging carrot seedlings are sealed in. 
  4. Remove the shadecloth when the carrot seedlings are pushing up against the bottom of the shadecloth.
    By then the carrots should be big enough to withstand attacks from slugs and snails, though you may have to apply further protection measures if there are lots of slugs and snails around.

slugs and snails

13mm polypipe sticks laid across rows of newly sown carrots (under the lighter sandy looking soil).

The same rows after 40% shadecloth has been placed across it.  The edges are held in place with a short star picket (top) and netting pegs (bottom).  The polypipe sticks keep the shadecloth just off the soil.

For extra protection against slugs and snails the edges can be buried in the soil.
Slugs and snails are the main threat, though only when carrots are in the seedling stage.  Options to control them are:-
  • Shadecloth
    Covering your carrot beds with shadecloth (described above) when the young seedlings are first emerging creates a barrier to keep slugs and snails from getting at your carrots, particularly if the edges of the shadecloth are buried in the soil
  • Iron EDTA pellets
    If have lots of slugs and snails in your garden you should consider sprinkling a few iron EDTA pellets under the shadecloth to get any small slugs that might slip through. 
    These pellets are much safer than the traditional metaldehyde snail pellets,  they pose no threat to cats, dogs, birds and worms, plus when they decompose they mainly break down into iron, which is actually good for soil.  For more information on iron EDTA pellets follow this
  • Hand picking
    A very effective way to reduce large slug and snail numbers in your garden is to go out with a torch and a bucket at night and pick them up by hand.  They can be disposed of by squashing, tipping into boiling water or feeding to your chickens the next day.
  • Flywire box
    If all else fails then you can grow carrots under a wooden box with flywire nailed to the top and the bottom driven well into the ground to create a tight seal.  The disadvantage of a flywire screen box is that you can't vary its size.  When sealed properly shadecloth does almost as good a job and is much more flexible size wise.
Though whitefly  won't kill carrot plants if their numbers build up enough they can lower productivity by damaging the leaves.  Options for controlling whitefly include:-
  • Plant spring onions
    When planting carrot seeds also sprinkle in a few spring onion seeds.  The pungent smell that spring onions give off will deter whiteflies, you will also end up with some nice spring onions to harvest.
  • Plant flowering plants that attract hoverflies.
    Hoverflies(small flies with beelike stripes on their abdomens) live off pollen so are attracted to flowers, however in their larval stage they prey on aphids and whitefly larva.  When I have lots of hoverflies in my garden in spring I usually have few aphids or whiteflies.  Plants that attract hoverflies include Waxplant and Thyme.
  • Pyrethrum spray
    This is a natural poison made from the pyrethrum flower, though be aware that it is still a broad spectrum poison, which means it will also kill beneficial insects such as lacewings and ladybeetles.  It should only be used if you have a bad infestation of whitefly.
There are  many other options for controlling whiteflies but I have found these have proven to be quite effective.
cockchafer grubs
Cockchafer grub, image courtesy of the internet.

LEFT: Damage to carrots caused by small cockchafer grubs.  RIGHT: The same carrots after they have been cleaned up using a potato peeler.
Cockchafer grubs are the larval form of the cockchafer beetle.  They are often found in lawns feeding on grass roots but they are also partial to root crops.  If their numbers build up enough  they can do fairly serious damage to mature carrots. Unfortunately the only effective pesticides are quite toxic and I do not recommend their use. 

The best defence against cockchafer grubs is to plant small beds of carrots that can be harvested within a fairly short period of time.  The longer mature carrots are left in the ground the greater the risk of damage from cockchafers.  You should also not plant carrots in a bed that has been planted with carrots in the previous season.

Mild damage to carrots by cockchafer grubs (signs being holes and indents) can be removed by peeling the damaged sections away with a potato peeler or knife.

Of course there are other pests that attack carrots but these are the only ones I have encountered.  I have yet to experience any disease problems with carrots.

Page created 27th May 2018