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jandtaa

Carrot Growing Guide

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Hi Loong

Here's a UK guide to growing carrots that includes a spacing recommendation. You could try increasing the spacing between rows to 30 cm's if you find excessive top growth is causing problems with rotting. Carrots are highly susceptible to a wide range of rots wiki guide to carrot disease

You're spot on with the idea of trimming back the foliage to help prevent disease these guys had the same idea !!

carrot foliage trimmer

Types of Soil /Climate and growing position 

Carrots develop normally within a great range of temperatures and are grown throughout the world with the exception for the very warmest areas. Carrots are tolerant of long days but need low temperatures to induce flowering. 

Carrots are fairly fussy growers. They love light, stone free, well drained, fertile soils with plenty of well rotted organic matter in them. Rich sandy peaty soils are perfect in providing the best conditions for the carrot roots to penetrate deeply and to swell. 

The pH value should 6.5 to 7.5 for best results. Potassium promotes solid, sweet carrots. Wood ashes contain soluble potassium which reaches the plant quickly. Excess Nitrogen causes branching and hairy, fibrous roots. 

It is much harder to grow good carrots in heavy clay soils or soils which are compacted or stony. Such conditions can cause the forking of roots. Water logged sites are also less than ideal. If you have a heavy soil, dig in plenty of manure several months before planting. Never work fresh manure into the soil as this encourages sappy growth and forking of roots. Add leaf mould to lighten heavy soil and rake in Nitrogen fertiliser before sowing a crop in poor soil. 

Early carrots appreciate a sheltered position but main crop need an open sunny site. Carrots should be rotated around the garden to avoid the build up of diseases. It is recommended that you grow them in a different bed each year over at least a three year cycle. 

Soil temperature can be critical for successful carrots. At temperatures below 5 ºC they will struggle to germinate. Slightly higher temperatures and they could take up to 35 days to start. 

If you wait until the soil is 10 ºC germination will occur within ten days. Basically if the soil is chilly to touch do not plant. 

Curiously even within a variety a carrot's colour and shape can vary according to the type of soil and commencement temperature. Lower temperatures give yellower carrots and reduced size and shape. 

Proper watering can make a difference. Carrots need 2cm of water from rainfall each week during the growing season. Soaking well when watering helps to promote good root development. 

Seed Sowing Methods 

Carrots are normally grown straight in the ground and then thinned in stages to obtain the correct distance apart. Never plant in cold or weedy soil as carrots are difficult to weed once established. 

Carrots are cool-weather vegetables, so start sowing about two weeks before the last expected frost in your area. 

Make successive plantings every three weeks but avoid the hottest part of the summer. 

Sow in drills about 2cm deep and 15cm apart. With this spacing the foliage of adjacent plants will make a dense canopy when the plants are mature. 

Place a 1cm layer of peat moss in the bottom of each furrow, 

Sow the seeds sparingly on top, then cover with about 0.5cm of soil. Seeds must be kept moist to germinate. Mulching with straw will help hold the moisture, and will also make it easier to water without disturbing the seeds. 

When sowing seeds, try to space them 1cm apart. The tiny seeds make spacing difficult, but it will be easier to thin without disturbing the plants you plan to leave, if there is a little space between them. Seeds can be mixed with sand to make sowing a little easier. 

You can try mixing radish seeds with the carrot seeds. The carrot seeds are slow to germinate, and the radishes, which germinate and grow very quickly, will mark the row until the carrots come up.

Thin the carrots out to 5cm spacings (the thinnings can be eaten as baby carrots)

Here's some further info on optimum temperatures:

Carrots are grown in the tropics where high elevations give cool night temperatures . Optimum growing temperatures for these crops are 15 to 20 C with a minimum of 5 C and a maximum of 24 C. . The optimum germination temperature for carrots is 25 C. The maximum temperature for germination is 30 C .Root growth is fastest at a temperature between 15 ºC and 18 ºC, while optimum temperatures for shoot growth are somewhat higher. Seeds of carrot may germinate at low temperatures but the germination period is shorter at higher temperatures and a soil temperature of at least 10 ºC is therefore recommended.

These crops therefore favour cool season conditions.

I also recommend mulching with rice straw which will help prevent green shoulders and apparently improves the sweetness of the carrots ! I think this could be due to temperature although yet to find any papers to confirm this.

cheers for now J

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I remember my father always swore by planting a row of onions between rows of carrots. He claimed it kept wireworm (I think that is what he called it) at bay.

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Well done Jandtaa, some good info there. I hope it will help me to get some better carrots when I start the next lot in October or thereabouts.

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No Problem Loong !

Gary yeah the alium family are recommended companion plants for carrots. Chives are supposed to be particularly good. They act as a deterrent against carrot fly, the smell confuses them. Not sure whether they work against wireworm (the larvae of the click beetle), although I know there is some research being done with mustard being sown and turned in prior to planting root crops.

cheers for now J

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Has anyone ever got flowers or seeds from carrots in Thailand ?

I got Oxhearts to grow good during winter.

I left some in the ground hoping they would flower,

but by the time the rains started they had rotted.

Now from Jandtaa's posting it says cold weather induces flowering,

so I might try planting some early October.

& maybe they will be mature enough by jan/feb to flower.

The european & US websites say take them out of the ground & store them in the cellar over winter.

replant in the spring & they will flower.

But I cant think how i could store them long enough in Thailand.

Any thoughts ?

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Hi Pondlife

From what I've read carrots, even if you can get them to flower will not set seed in the tropics so it could be a bit of a challenge. If I remember rightly I think there is a guy in Brasil who has successfully bred a couple of varieties of open-pollinated carrots that will set seed but I cant find the link amongst my bookmarks.The problem is that carrots are biennial and spend a cold season before flowering in the second year.I checked out the method of saving carrot seed in the "seed savers hand book" and if not grown from seed to seed the carrots are harvested the best roots are selected stored over winter and then replanted to flower.Possibly a spell in the fridge could induce them to flower.

cheers for now

J

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Hi Pondlife

Managed to find aforementioned bookmark (Opera browser now has an entire history search function).The variety is called "Uberlandia" here's some info on it;

UBERLANDIA CARROTS WILL SET SEED IN THE TROPICS. In the spring of 1992, William Tabeka wrote from Uganda. He wanted to grow carrots, but seed was not available. We sent information on the difficulties of producing carrot seed in the tropics. Carrots are biennials; they normally spend a winter dormant in the ground, then produce seed the second year. We also enclosed just a few seeds from a packet we had just received from Dr. Warwick Kerr in Brazil. He said that this carrot, called Uberlandia,' would set seed even in the tropics, and would do so in a single season.

Our interest in this carrot increased greatly when Mr. Tabeka sent us this picture of himself standing by what appeared to be carrots in full bloom. I wrote right away inquiring if that is indeed what I saw, and what he thought of the taste. He replied, "I assure you that the carrots really did put on seeds. The taste of the root is good and there is a difference, because that one which put on seeds has a root that is a bit longer than the others (some high carotene carrot seeds we had sent). There is no difference at all in the appearance of the seeds." A recent letter says he is now growing carrots from seeds that he harvested during the last rainy season.

We planted a few plots in the spring to produce seed for our seedbank. By early summer, they blossomed heavily and eventually produced seed. We need to work on timing to see if we can get seed during the dry season, as the heat and humidity of our rainy summers make it difficult to obtain high quality seed. Nonetheless, we can now offer our network seed with about 70% germination.

We allowed most plants to go to seed, so we have little information on size or taste of the roots (by the time seed was mature, the roots had shriveled up). I sampled two 3-inch carrots, trying them both raw and boiled. I prefer the varieties I am used to, but if they were the only carrots available, I would be glad to have them. In other trials, we found great variation in the plots, from commercial-sized, bright orange carrots to small yellow roots. Someone familiar with plant breeding could do a great service to the small farmer. Presumably a variety with superior qualities could be developed which would also still produce its own seed. ECHO has plenty of seed, and we continue to select better-quality carrots each year. If you try this seed, we will be VERY interested in your experience with and impressions of this carrot.

Dr. Kerr provided more information about these carrots. "Carrots do not usually flower in the tropics. Eighty years ago a group of Portuguese growers planted carrots from Portugal and the Madeira Island in the southernmost state of Brazil. Some of these plants flowered and produced seed. Plant breeders from Sao Paulo and Brasilia independently collected seeds and developed varieties called 'Tropics' and 'Brasilia.'

"I used these two in my work at the Federal Universities of Maranhao and, currently, of Uberlandia. For five generations I selected the best carrots using the following criteria: (1) size between 12-18 cm, (2) parallel sides, (3) red xylem, (4) resistance to local diseases, (5) late flowering, (6) no green on the top of the root. I call the resulting cultivar 'Uberlandia.' The vitamin A content (carotene) is between 9,000 and 11,000 I.U.

"It is advisable that people who grow the carrot in other areas carry out their own selection. Here is how to do it. After 90 days dig up all the carrots. Select the best 30 according to the above standards or standards of your own. Re-plant these carrots right away and allow to go to seed. The red xylem can be observed by cutting 3 cm of the inferior tip (narrow end) of the carrot. Discard if the xylem is yellow."

Dr. Kerr has made a great contribution to third world gardeners. In the USA, nearly all work by private industry and much of the work done at universities is for a hybrid so that people will need to purchase seeds each year and money will be available to fund research programs. We need more breeders working on seeds for the poor. 

Seed is available here ECHO seedbank

hope this helps J

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I remember my father always swore by planting a row of onions between rows of carrots. He claimed it kept wireworm (I think that is what he called it) at bay.

Think Carrots deter onion fly, and visa versa onions deter carrot fly, also in the Uk carrot fly only flies about 2 fet above ground so a meter of fine mesh screening the carrots can physically keep them away.

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Thanks J, That sounds very promising.

I'll try to get some as soon as I have time.

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This is the 4th year that I have grown carrots in the CM valley [in my backyard garden] and have always harvested them young and sweet....thumb sized at most. This year, I made a bigger area for my carrots. Sowed seed inOct/Nov in well tilled clay soil with lots of rice hulls and klab dam and a little manuer to loosen up the soil. I simply mixed a teaspoon of carrot seed with a small bucket of fine sand and broadcast seed/sand in the row and got even germination. Covered seed/sand with klab and and covered with rice sacks to keep moist.

then when they get thumb sized, I harvested those small tasty young carrots, thinning them down at the same time to about 2 inches apart.

This year, I let a large row continue to grow and have had carrots continuously for 5-6 months and now that the rains have started, the rot is comming on, so we just yanked them out yesterday. Maybe with plastic cover, we could have slowed down the rot.

My largest was as big as those monster [tasteless] Chineese carrots they sell in superstores, but still had good flavor.

Conclusion.....carrots can be grown in heavy clay soils if properly prepared and watered lightly during the dry season, but not the wet. Too much manuer/nitrogen will cause hairs to form on carrots...still taste sweet, but have to use a stainless steel sponge to remove.

great crop.....

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I just ordered 2 packs of Uberlandia from ECHO.

Their selection of other seeds was a bit poor.

I'll let you know how they go & seeds will be available if sucessful.

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This is the 4th year that I have grown carrots in the CM valley [in my backyard garden] and have always harvested them young and sweet....thumb sized at most. This year, I made a bigger area for my carrots. Sowed seed inOct/Nov in well tilled clay soil with lots of rice hulls and klab dam and a little manuer to loosen up the soil. I simply mixed a teaspoon of carrot seed with a small bucket of fine sand and broadcast seed/sand in the row and got even germination. Covered seed/sand with klab and and covered with rice sacks to keep moist.

then when they get thumb sized, I harvested those small tasty young carrots, thinning them down at the same time to about 2 inches apart.

This year, I let a large row continue to grow and have had carrots continuously for 5-6 months and now that the rains have started, the rot is comming on, so we just yanked them out yesterday. Maybe with plastic cover, we could have slowed down the rot.

My largest was as big as those monster [tasteless] Chineese carrots they sell in superstores, but still had good flavor.

Conclusion.....carrots can be grown in heavy clay soils if properly prepared and watered lightly during the dry season, but not the wet.

Too much manuer/nitrogen will cause hairs to form on carrots...still taste sweet, but have to use a stainless steel sponge to remove.

great crop.....

Hi Jaideeguy

What type of carrots are you growing in CM? I would like to try planting some. Thanks

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My best was a Nantes type with a blunt end and shorter, but last year, I just planted the locally available type with no name and they did well until the rain/rot.

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