New raised veggie beds are all turning yellow! Help!

[Lavalampy]

Help! I just moved to North Carolina (not far from Greensboro) and I was SO excited to have a garden. I got cedar raised beds and filled them with what I thought was good soil. I did a thin bottom layer of a mulch like mix that was made of aged pine bark fines and cow manure, then the majority of the beds were filled with a mix of 35% "top soil" (whatever that is), 35% aged fines, 30% cow manure. Then I put a little bit of potting soil that the gardening center I went to recommended for raised veggie beds. I planted according to a square foot gardening method garden planner tool I found on a gardeners website. Everything looked fantastic at first. The transplants (tomato, pepper, cabbage, broccoli) grew very fast and the seeds all sprouted up in a week, and I was getting ready to thin things out. But then it all went downhill! The leaves on the bottom of most of my plants started turning yellow, curling or drooping off. The growth of almost all plants now seems very stunted, and the last few seeds that had sprouted up haven't grown since (cauliflower, arugula). My plan right now is to get a pH testing kit and see if that reveals anything, but I've also read that those kits can be inaccurate. I'm wondering if this pattern is more consistent with a nutrient deficiency, perhaps nitrogen or magnesium??

help!! I'm so afraid I'll lose them all!

[rainbowgardener]

Yup, nutrient deficiency, specifically nitrogen, but maybe others as well.

1/3 "topsoil" which as you noted may indicate anything including what they dug out to dig foundations; 1/3 bark fines, which are very high Carbon and tie up a bunch of Nitrogen in the process of breaking down; and 1/3 manure. That is a lot of manure and it is a source of Nitrogen. But it takes a long time to break down and start releasing the nitrogen.

"The nitrogen in manure is not all available to growing plants the first year as much of it may be tied up in organic forms. Organic nitrogen becomes available to plants when soil microorganisms decompose organic compounds, such as proteins, and then convert the released N to NH4. This process, known as mineralization, occurs over a period of years...In general, about 30% to 50% of the organic nitrogen becomes available the first year. Thereafter, the amount gradually decreases. A general estimate is 50% the first year, 25% the second year, 12.5% the third year, and so forth. Cow manure is about 1% N. It is used because it is also a good source of micronutrients like zinc and it is biologically active. ... Salt content may be high in fresh manure and decreases with exposure to rains and irrigation as salts are leached out. Continual and/or heavy applications of manure can lead to a salt build-up.

To avoid salt problems associated with the use of manure or compost made with manure, limit applications to one inch per year (when cultivated six to eight inches deep) and thoroughly cultivate the manure or compost into the soil.

https://www.ext.colostate.edu/mg/gardennotes/242.html

So so far your plants are getting very little Nitrogen. They need a good quick release form of N while you wait for the manure to break down more.

see this thread for someone with similar issues: https://www.helpfulgardener.com/forum/vi ... =4&t=64356

[applestar]

Also, some of the crops you mentioned are not really suited to growing in the summer. Even tomatoes shut down or die during the heat of the summer....

[imafan26]

The other thing that would make the lower leaves yellow besides nitrogen and senesence would be if your bed is holding too much water. If it has been raining a lot or if you are watering more because your plants look yellow, the roots may not be too happy about that.

[Lavalampy]

Thanks all! I have added some nitrogen.. And it's true, I was worried that I was under watering and had been doing that a bit more. Fascinating about the nitrogen being bound up in the manure for so long- I had no idea!

[rainbowgardener]

Manure is not actually a very rich source of Nitrogen, being about 1%. A balanced 10-10-10 fertilizer is 10% N. The difference is that you can use manure (as long as it is well-aged) by the shovelful. Synthetic ferts are used by the tablespoon (per plant) or the plants get burned.