Too Much Fertilizer?

Asked June 21, 2014, 9:08 AM EDT

I fear the horse manure we used in our flower bed was too "hot". How can I neutralize the soil? My annuals & perennials planted in mid-May have hardly grown at all and I believe they're overfertilized from the manure. Can something still be done this year or do I have to wait till next spring? I'm in Zone 3.

Morton County North Dakota

3 Responses

First, maybe we need to be patient. This has been a very late and cool spring. We are weeks behind. We need some heat for plants to get going. My tomatoes, for example, have barely grown at all.How fresh is the manure? Was it fully composted when used? Fully composted manure will appear like soil and have minimal smell. It takes about 6 months for fresh manure to become fully composted, but this is dependent on temperature and whether or not the manure pile was turned during the composting process.'Hot" manure will cause desiccation of plant roots. The first aboveground symptoms will be drying along leaf margins. If the soil is too rich, but not to the extent of burning the plants, you will see luxurious vegetative growth and reduced flowering. Keep your eyes open for that. As far as neutralizing the hot soil, the best options would be to try to leach the harmful salts in the manure out of the soil. Deep waterings will help. Don't flood the plants, but you get the idea. We want to flush the salts out of the soil. Aerating the soil via cultivation can speed up the decomposition process, too. Be careful not to damage the roots of your flowers. The soil should be fully composted by next year. Hopefully everything will work out this year, too.

Thank you so much! I figured as much but also wanted to have you evaluate my situation too. Having grown up on a beef ranch, I'm used to using well-composted manure from grass fed/hormone free cattle, for everything we fertilized. But the horse manure is something I haven't used much.
Actually, the manure was not fully composted as it should be..{sigh} Hence the problems. I have been watering more and am seeing a little better growth. Thank you again for your wonderful and timely help. Hopefully next year by following your suggestions, the flower bed will be ready...and I can proceed with perennials. This year (on a gut instinct I suppose) I went with simple/cheap annuals...."just in case". Turns out it was a good thing ;-)

You are welcome.Good luck!