In early July, Anthony Penny faced a similar crisis. Penny, who primarily grows produce, had decided to branch out into mum production. He figured the crop would pair well with his other fall items: pumpkins, gourds, onions, cabbage and sweet potatoes.

Three weeks into production, however, the mums developed a bleached-out appearance. 

Like Harmuth, Penny went straight to the Agronomic Division for advice. Pettit and Penny discussed the fertility program and production practices for his entire operation. Pettit suggested comparative soilless media tests instead of plant tissue analysis because the mums were at such an early stage of development.

Test results indicated that both magnesium and sulfur were especially low.

 Penny followed Pettit’s recommendation to apply Epsom salt through the drip system twice a week at a rate of 40 parts per million sulfur. The new fertility program caused a growth spurt, and the crop improved significantly.

By mid-August, however, another deficiency manifested itself — yellow tops with interveinal chlorosis. This time the plants were large enough to make it practical to collect leaves for tissue analysis, and this test indicated iron deficiency.

“Penny was using a 20-20-20 fertilizer that contained 1.5 parts per million iron,” Pettit said. “I figured the mums needed 50 to 75 percent more iron so I suggested a new course of action. For his vegetable crops, Penny was already using a 3-15-27 grade fertilizer that contained 10 percent sulfur and twice as much iron as the 20-20-20. By using 3-15-27 on the mums as well, he could take care of the sulfur and iron issues at the same time.”

Penny liked the idea of using the same fertilizer for both sets of crops. He switched fertilizers in late-August, and by mid-September, the mums had grown so much he couldn’t walk between them. He had 2,500 plants come into bloom just in time for sale at the State Farmers Market in October.

Harmuth and Penny are both regular vendors at the Raleigh market. Pettit enjoys strolling through the market on the weekends and is gratified by the success of growers he has helped. 

“These services pulled me back from the brink of economic disaster,” Harmuth said. “They are valuable and the charge is nominal. I’d highly recommend them to anyone.”

Agronomic Division services are available to all greenhouse and nursery producers who encounter critical nutrient problems. The base fee for most plant/waste/solution/media tests is $5 per sample, but there is some variation so refer to the comprehensive schedule available at

Services include soil testing; nematode assay; analysis of plant tissue, waste/compost, nutrient solutions, irrigation source water and soilless media; as well as field consultations.

Growers who live in the Wake County area may prefer to come straight to the Raleigh office for assistance, but others may wish to contact their local NCDA&CS regional agronomist. See

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