Carrot science

Carrots under burlap

Welcome to my carrot lab! Carrots have been my biggest early spring headache. In cool weather, they take forever to germinate, 2 or 3 weeks, and by that time, the chance of weed competition is pretty good, and just about anything growing around the tiny seedlings makes excruciatingly time-consuming surgical hand weeding a necessity. What to do? Last year, I tried IRT (plastic) mulch over the bed. This worked great, heating up the soil, speeding germination to 7 days, and keeping weeds down. Problem was, miss the germination window (when a good number have emerged) by a few hours or a day, and the seedlings got toasted in the heat. Too delicate a balance. So, a new approach, something I’d read about. It involves a double layer of (untreated!) burlap. Simple. The burlap acts as a mulch to retain moisture and increase soil temperature, and it also allows in water and some light. What could be easier?!?! Now, all it has to do is WORK! (Update: it worked like a charm…)

21 thoughts on “Carrot science”

  1. If you have to deal with precise weeding by hand, there are several new long-handled weeders that are designed for agriculture, such as carrots. These are very precise tools that can help you carefully weed your cash crops without breaking your back.
    Search for ‘precise weeding tools’ on the web for some suggestions.

  2. Hey Ray,

    “Human hybrid weeding machine”You sure have a lot of weed info and weeding tools on your site!! I found particularly intriguing the news (with photo!) that “one of the latest developments for mechanized hand weeding is a controversial human-hybrid weeding machine which supports several workers prostrate on their abdomens and allows them to pull weeds by their hands.” Yikes! I won’t feel so unusual if I ever have to crawl along saving a few hundred feet of carrots or green onions by hand again…but maybe I’ll feel like an oppressed and exploited migrant farm worker… Hmmm.

  3. hey mike,
    We use burlap for germinating our carrots and it worked unbelievably great last year–I read about it on An unseen benefit for us was that the weeds grew faster than the carrots and they would actually grow through the burlap. When we pulled the burlap off, we would pull a batch of the biggest weeds with it, but the baby carrot seedlings would be untouched. Your fields look great!

  4. Laura: So it’s gonna work for sure!! :) I think I read about burlap in the same place you did, a year or two ago in, it was an interview with a guy known far and wide for his carrots, something like that. The weeding effect sounds like a bonus. I’ve noticed a couple of blades of grass poking through, but no weed action yet… This is exciting.

  5. Hand weeding is a last resort and a costly one after using other means for weed control. Preventing weeds by mulching is certainly the best approach and one that should be continuously applied and perfected.

    We all need to be a little more sensitive to the way our workers actually feel when they do strenuous work for weeding and harvesting, for example. In the case of the human-hybrid weeding machine that you noticed on, it’s very possible that the employers did not have a clue as to the true feelings of their workers harnessed to the flat bed weeder. Part of the problem is that the workers are afraid of complaining because they may lose their jobs and possibly be deported.

    Farmers and other employers of migrant workers have tremendous power over the lives of their workers. If you treat your workers well, they will also reciprocate in whatever way they can. Goodwill can be spread much like the nutrients we use to grow our crops.

  6. I’m from England. My carrots won’t germinate – found you on website where you said you had covered field in burlap with great germination success. What is burlap?

  7. Mary: Burlap! It’s that coarsely woven fabric they used to make potato sacks and the like from, before plastic mesh. I managed to find some in 4′ wide rolls at a garden center, I believe it was used in landscaping and nurseries to wrap the roots of small trees and shrubs for transplanting, uses like that (before…plastic).

    If you’re growing only a small garden amount, you could try plastic mulch, or even a black garbage bag, instead of burlap. Cut open the bag to only one layer, place over your seeded carrots and pin or bury or weight the edges so it won’t blow away. The mulch will create extra heat to speed germination, and suppress weeds that need light to start (carrots don’t). You should get germination in around 7 days, with no weeds! The plastic will also maintain moisture, you shouldn’t have to water if you water in well just before mulching.

    IMPORTANT: you have to check every day, from day 5 or so, because once the carrot seedlings have emerged, the heat under the plastic can kill ’em off in a few hours. As soon as you see a few up along your row, take off the plastic and make sure to keep the bed moist for the next couple of days to encourage more germination. This is a bit of an extreme method because of the heat generated, but otherwise, carrots can take 3 weeks or more to emerge, depending on the temperature and moisture, they can be real slow… Burlap is gentler, because it doesn’t get as hot, but it doesn’t raise the heat as much and allows weeds to start—it works when you have lots on the go. Oh, don’t use clear plastic, it’ll get REALLY hot and also allow weeds to grow. Hope that helps!

  8. First. So glad I found this blog…I LOVE it!
    This probably would be too time consuming for you and for your needs, but I germinated my carrots this year using the wintersow method
    I had 100% germination! I sowed them on April 13th and by April 22nd there was about 40% up and within another week 100% . They transplanted well yesterday into prepared carrot area just as 1st true leaves began to emerge! These carrots are Purple Dragon (my pic say P. Haze but messed up).
    Have used this method of recycled container sowing since winter/spring 2003 mainly for annuals/perennials, but have also works well for collards, mustard, kale, broccoli, chard, lettuce, ect. Sow them and forget about them, but then I’m not maintaining a tiny farm either!!

    Carrot photo
    Containers photo

  9. Vera: That’s a great article on winter sowing. It’s kind of like mini-coldframes. I’m definitely  going to try this winter (well, I definitely INTEND to…). I don’t know how well it would scale for bigger quantities, but it’s so interesting, one thing may lead to another. Every winter, I intend to direct seed a couple of things like spinach and maybe peas, really late, so they’ll germinate in spring, but with such unpredictable winters, chances are it’ll warm up and they’ll germinate before the final freeze-up. Wait too long and the ground is too hard… Anyway, cool. Thanks!

  10. HI:  I have burlap and I would like to use it as mulch to completely renew some lawn that has gone very weedy.  I wonder how long the burlap would take to completely decompose.   For example, if I covered my front lawn which is in complete sun)  with burlap this spring, would the burlap decompose by say, next spring.  I am in Toronto so we get snow cover most winters. 

  11. Marg: My experience has been with trying to germinate seed and preserve the burlap, so I’ve been doing the opposite of what you want! Untreated burlap does break down really nicely, but I’m not sure of the timeframe. A year sounds good for a layer or two.  I took a quick look online, this burlap compost blog post is kinda relevant.  Hope that helps!

  12. Hi guys. I’m from Lahore, Pakistan, planning to start a garlic farm. My question is regarding soil improvement.
    Can anyone please guide me regarding Humous/ Humic Acid. It appears that The Compost/ Farm Manure/ Chicken Waste all are put in the soil for the purpose of creating Humous.
    If i can put Humic Acid (Powder) in the soil, is it a replacement to all of the above?

  13. Hi there Bilal Shah,
    I would love to hear more about your garlic farm project. My thought about the humic acid is that the microbial action of real compost is as much value as the humic acid. The acid is a by-product of the action of the microbes that build the soil structure. It is this living structure that you want as much as the acid its self.  This structure will help hold soil moisture etc. Any sort of  compostable materials can be balanced to make a good, live compost. The humus its self is stable and will not leach out of the soil while the humic acid could just leach away. Best of luck with your plan.

  14. For carrot germination, I use a local product. I live near a factory that makes erosion control blankets. These are rolls of wood excelsior (thin curls of wood) that are sandwiched between plastic mesh. THey are used by the highway department for covering new soil and getting it seeded down.I buy the “seconds” that have a few bare spots in them for an inexpensive price. Make sure you get the ones with mesh on both sides so you can roll them up again. They last all summer. These keep the soil damp and the carrots germinate really well. They also help cool the soil when trying to get fall spinach to germinate in warm soils of last August.

    • Interesting about cooling the soil for summer spinach germination. Although cover would generally keep things warmer, I suppose if the cover is reflective, it could fend off a few degrees during a full-on sunny summer day, and that could make all the difference. Haven’t had a problem with summer spinach germination recently, but it has happened. I’ll keep this in mind to try next time that comes up. Thanks for sharing. :)

  15. Could you seed the carrots and leave the burlap on? I’m wondering if the burlap would decompose by the time the carrots were ready to harvest? Anything else you can direct-seed under burlap? Or can you leave burlap in the garden to cut down on weeds, cut holes in it to transplant into?

    • No, once they germinate, they need sun, so you should remove the burlap. I’ve stopped using it in favor of landscaping fabric – cheaper, easier to manage, although unfortunately synthetic as well – and that really lets in no light. This season, I am also trying old row cover (2-3 layers) instead of burlap, that lets in a lot more sunlight, but it also won’t suppress weeds, and you’d still want max sun, so you’d want to take it off, too.

      You could cover just about anything. Far as I know, just about all of our North American garden vegetables and herbs don’t need light to germinate, and can benefit from the increased warmth and moisture under cover. But it is more work, and usually unnecessary for most other crops.

      Experiment! :)


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