My Danver carrots (NE z7a) also grow shorter and wider than expected. Last year I dug down to loosen the bed soil, to insure no rocks and to add sand to lighten my soil, which helped. I also thinned the seedlings more which was part of my issue.

Watering appropriately (I use drip lines) and not over fertilizing helps too.

Short or long, hopefully your carrots are tasty!

Have you contacted your local extension office and got professional advice on how to grow carrots in your area? Have you had your soil tested? You might be completely missing a vital ingredient in your soil. You have said that compost is not a fertilizer, are you adding enough lawn fertilizer?

To what depth is your bed friable? Carrots need good food and water, true. But often a short carrot is due to the friable depth not being enough. Danvers is 6-8 inch length on average. you should have your bed friable 12+ inches- half for the carrot, half for it's root tip. The questing tip of the root tells the carrot how big it can get. If you are adding amendments, and only digging them in a couple-few inches, try digging deeper.

Probably as others have commented, deeper cultivation. But maybe they packaged up a short variety by mistake? I grow mostly the Nantes/Touchon variety which are semi-short but very sweet. I did add in an Imperator this year which is longer and the only problem was needing a shovel to dig them up. About the roots growing deeper seeking moisture, that seems to be a given for most plants?

Here's the latest harvest of all 3...

Bed is highly friable and well amended with compost to a depth of at least 14 inches. I load on compost and turn the soil over at least to a shovel depth. Many of my carrots are only 4 inches long. My soil has been tested almost yearly. I have PLENTY of all nutrients. Appropriate thinning might be an issue. I tend to skimp a bit on spacing, but I would think that putting them too close together would affect both width and length, and not just length. Mine are plenty wide.

I'd consider Roberts advice, and I'm not trying to be rude but you always insist you have plenty of nutrients, and I'm wondering if you ever fertilize at all over the season relying solely on a soil test. Carrots are short rooted plants just like onions so their roots don't go deep or spread far. Denitrification happens very fast in the top soil with microbes in direct competition with plants for nitrogen. Top soil nitrogen is lost in a few weeks or even a few days being used by plants and microbes, denitrified or leached as nitrates deeper beyond the root zone.

Fertilize with a little 1-0-3 or 1-2-3 ratio fertilizers 3 or 4 weeks after they come up and a again mid season with more than the first fertilization. Carrots don't need a lot of nitrogen but there still needs to be a careful balance between foliage tops to root bottoms. Let your plants show you what they need and not a a soil test that will change daily for nitrogen. Carrots will respond very fast to nitrogen and easily seen in the foliage in just a few days, and good tops are required to supply the storage roots with sugars, because they are biannual and the reason roots get big to begin with.

years ago I thought I had enough nutrients after one and done broadcasts of fertilizers prior to planting but usually had short carrots and never fertilized after planting. One year I threw some Potassium nitrate (13-0-45) on my pathetic looking carrots and they went wild with better looking tops in a couple days, and a dim light went on. Later on when I checked for size they had turned into horse carrots, and some could choke a horse at a foot long, with some bolting meaning I may have applied to much nitrogen, and the light got brighter. Tweaking the amounts and fertilizing two times now gives me nice sized carrots, but now I add just phosphorous before planting and the nitrogen and potassium during the season. But instead of expensive potassium nitrate I use potassium chloride and Urea.

I add nitrogen, somewhat regularly, but EVERY soil test I get says that I have plenty of everything else. Not sure why you doubt that. .Granted that nitrogen tests are not dependable. But I am reluctant to use a lot of nitrogen with root vegetables because it's well understood that nitrogen benefits greens and not fruit. Now, I have plenty of carrot. These are big carrots. They are just stubby. My tops look fine. The issue isn't getting more carrot. It's about getting them shaped properly.

Looks like you've taken into account most possible reasons for stubby carrots Dan. I know how hot it gets in central Texas and it could be the reason. Carrots are considered a cool weather crop and if soil temperatures stayi above 75 degrees it will cause stubby carrots, and also soil temperatures below 55 degrees. Could your soil temperature stay to high when growing your carrots? It's a cause to consider so tweaking your growing season for carrots could correct the problem. If you don't use a heavy layer of mulch around your carrots It may also be something to try. A hot sunny day can heat soil considerably in just one day.

Yes, except this is winter in Texas. Our temps don't get much above the 70s now, and we were down in the 20s and 30s last week. Median high temps in winter here are in the 60s. I don't grow any root veggies in the summer. I should say that in previous years, they've looked pretty normal.

Danvers is an old variety, often called "Danvers half-long" because they are shorter and stumpier than other carrots, which is useful when you don't have great soil. I'm a fan of Danvers for that reason. My bet is that your problem is your choice of cultivar, not your cultivation of them. I'd buy some different carrots. Look at some seed catalogues and pick one that is long and skinny and plant them and the Danvers side-by-side.

I'm not sure if that makes sense. I have, more specifically, Danvers 126 (from Botanical Interests). Yes, that's a "half-long" variety, and that specific variety is quoted everywhere as having an expected length of 6-8 inches. Mine are coming out 4 inches (with a top diameter of more than 1 inch). Goodness knows how long a "full length" carrot might be! I have great soil, BTW.

Imperator type carrots are full size and get up around 12 inches long as do some Asian varieties like Kyoto Red. Danvers 126 is essentially an improved strain of Danvers Half Long and max out around 6 to 8 inches. Nantes and Chantenay type carrots are also in the same size range as Danvers, and Red Cored Chantenay always did well in my clay-ish soil (although so did Danvers). Perhaps try a few varieties next year and see what does best.

You say you dig down to at least a shovel's depth and that the soil is friable, but does the soil stay loose throughout the growing season? Or does it compact as the season goes on?

Also, you say you amend with plenty of compost and add nitrogen regularly (although you're reluctant to with carrots and root vegetables). I'm wondering if it could be possible you are adding just a bit too much nitrogen to hinder some root growth but not enough to cause forks or hairy roots...

Lastly, any pests like nematodes, root flies, woreworms, or weevils around? (Unlikely since you mention no damage but it's worth asking.)

Rodney

I too have to wonder if the carrots are getting too much N, though the tops don't seem to be oversized. All soil compacts as the growing season goes on. But I have no trouble sticking a shovel into it at the end of the season. No clay at all. No bugs of any kind that I can see, though not clear why they would make for stubby carrots. That's interesting that full size carrots can get to be a foot long. I have Nantes in another bed (though not mature.) I thought they were supposed to be shorter than the Danvers.