Gardening with Gary

Gardening Advice from an Expert

Broccoli

Nancy writes~ My broccoli de Cicco is 10" tall and has not headed. Should I fertilize it? I gave it phosphate.

A. “Broccoli” can mean different things to different people. When most people think of broccoli, they are thinking of sprouting broccoli (often referred to as “Italian” or “Calabrese” broccoli). “Heading” broccoli is not a broccoli at all—it is a late season or overwintering cauliflower. Another broccoli, broccoli rabe, does not produce a head and is used as a greens crop.

Broccoli de Cicco: An old Italian variety, fine flavor. Small central heads and many side shoots after first heads are cut at 3-4 inches. Non-determinate heading makes for a long harvest time.

Soil pH should be 6.5 or higher. Soil pH over 6.8 is necessary to manage club root.

Broccoli and other cole crops may be grown on a variety of soils but it does best on a well-drained, loam soil well supplied with organic matter. Sandy loams are preferred for early crops.

If soil is below pH 6.3 and/or the Calcium (Ca) level is low, lime should be applied. Use a soil tester. Test for levels of N, P, K, S, Mg [magnesium] and B: apply as needed nitrogen, phosphorus, potassium, sulfur, magnesium and boron. Broccoli is sensitive to boron deficiency. Lacking Nitrogen leads to poor heading.

Yellow flowers may appear before the heads are ready to harvest during periods of high temperatures. Planting too late in the spring or failing to give the plants a good start contributes to this condition. Premature flower development also may be caused by interrupted growth resulting from extended chilling of young plants, extremely early planting, holding plants in a garden center until they are too old or too dry, and severe drought conditions.

Small heads that form soon after plants are set in the garden are called "buttons" and usually result from mistreated seedlings being held too long or improperly before sale or planting. Applying a starter fertilizer at transplanting gets the plants off to a good start but cannot correct all the difficulties mentioned.

From: U Illinois

BROCCOLI HEADING DISORDERS:

Blindness: A percentage of the plants in the field form no heads at all due to some injury. The plant responds by producing numerous shoots at near ground level. The injury can be due to insect (cabbage maggot, lygus bug, diabrotica) damage to the growing point usually when the plant is small, or if these occur just at the beginning stages of head initiation.

Leafy heads: The presence of leaves within the head is often due to high temperature coupled with lush growth due to excess water and nitrogen.

Large, coarse buds: Bud size is a function of variety, but all develop large buds as the heads become mature. High temperature may result in excessively large or open buds.

From: Oregon State University