Started container carrots (on 8/7, Sweet Petite) for my first time & with what I've read, I'm probably using too much nitrogen (Jack's triple 20). Do they look like they're going to tops?
Yep. That - Jack's Triple 20 - is a lot of nitrogen. A lot P and K too for that matter. How often are you applying it and how?
Too much Nitrogen usually causes Carrots to fork. Not sure it would cause it not to grow roots. If you fertilize where you are growing Carrots, it would be best to do it in the fall, and plant the Carrots in the Spring. Don't plant the Carrots in recently fertilized areas.
They probably also like soil that is not so friable. Not sure if that's true though. I planted carrots in a spot that was only slightly loose, and they grew huge. I haven't harvested them yet, but they are big.
I tried container carrots this year and didn't have any luck. None of them grew to anywhere near full size. I've seen other people have more success with them in containers, but I won't bother next year - it would take too many seasons to get it right.
I doubt small roots are a nitrogen problem. I did have some hairy roots this year in my garden plot. I must have fertilized once too many times.
It is the ratio of top to root in the photo that is the give away. Just like many other root vegetables (radishes, beets, turnips, etc.) excess N gives you big tops and little to no root.
But I do agree with stuffradio that timing of fertilizing is also important. No sooner than 6 weeks prior to planting and 8 weeks is better, then a light side dressing of a low N fert in mid-season.
Too much nitrogen will give you big roots and big tops. It will also lower the sweetness of the roots. I know this is true for sugar beet. Grew them for 30 years. Too much nitrogen was the worst thing you could do. It made lots of impurities in the root which caused sugar to be tied up in molasses. Total sugar was reduced, extractable sugar was reduced even more, but root yield was increased by high nitrogen. We got paid by the ton based on extractable sugar.
I'm pretty sure carrots will respond the same as sugar beet. Use a moderate nitrogen rate early in the growing cycle. Then hope that the plants run out of nitrogen in late summer. Sugar will be highest in late fall and winter.
@ Yep. That - Jack's Triple 20 - is a lot of nitrogen. A lot P and K too for that matter. How often are you applying it and how?
Been fertilizing about every three weeks using a watering can... Remember this is a container...
I used Jack's 20 and mine did fine. I didn't fertilize a lot though. Half strength every month maybe.
Are you using it in a diluted form as is usually recommended in containers? Containers need feeding more often true but it also concentrates the fertilizer in a confined space so using diluted feedings is usually recommended - 1/4 to 1/2 strength max. Cut the Jacks to 1/4 strength.
Thanks Dave! Yeah, I've been using one tablespoon per gal of water....... Obviously need to cut that back to a 1/4 .............
An infallible fertilizer application for carrots is the one used by Alan Chadwick in his many garden projects during the period from 1967 to 1980. After cultivating the soil, apply about 2" of well rotted cow manure and a light dusting of bone-meal. Work that into the soil to a depth of around 6" and then sow your carrots into that. You shouldn't need to fertilize again at all. Any amount of compost worked into the soil would help. It's so gentle and balanced that you wouldn't need to worry about too much top growth. The following link has some very useful information and photos.
Here is a link that might be useful: Alan-Chadwick.org