Do you have space for artichokes?

Artichokes can be grown practically anywhere, but it is a large plant, averaging 4 to 6 feet across, so be sure to give it room to grow. They prefer cool, moist summers (or relatively shady spots) and mild winters. The majority of the commercial crop is grown in the central, coastal areas of California. While most artichokes are grown as annuals, the plants can actually be grown as perennials, producing edible buds for 4 or 5 years. Under the right conditions, you may be able to harvest as many as 30 artichokes per plant per year. To get the most out of your artichoke plants, it is important to provide light soil (add compost!), water in summer and improve drainage for winter.


Artichokes & temperature

Timing is critical when starting artichokes from seed and when selecting varieties. The heirloom varieties (‘Violetta Precoce’, ‘Green Globe’, or ‘Romanesco’) are very temperature sensitive and will not grow well in northern regions. ‘Opera’ and ‘Imperial Star’ are better choices for colder areas. ‘Green Globe’ and ‘Imperial Star’ perform the best in Santa Clara County.


Artichoke varieties & propagation

Artichokes are either green or purple. Traditionally, artichokes are a warm weather crop that can be propagated vegetatively or by planting seeds. Varieties that perform better through vegetative propagation include Italy’s large purple Romanesco, Spain’s medium green ‘Blanca de Tudela’, and Peru’s spend ‘Spinoso e Inguano’. Vegetative propagation refers to division and root cuttings. Division means separating the crown and roots that many herbaceous perennials produce on their own as a means of asexual reproduction and planting each separately. Root cuttings can be taken from established plants and placed in a favorable growth medium (moist soil) and allowed to create a new stem and become a complex, independent plant.


How to grow artichokes from seed

Many varieties of artichoke perform well when grown from seed, but it may take a period of vernalization before flowering begins. Green ‘Harmony’ or ‘Symphony’ and purple ‘Opal’, ‘Concerto’ or ‘Tempo’ can all be grown from seed. Since artichokes have deep taproots, they are not well suited to container gardening. Seedlings should be handled very carefully when transplanting. It is easiest to simply plant them in the ground where you want them to give the taproot the freedom to grow deeply, without interruption. Artichoke seeds should be sown 1/4 to 1/2 inch deep at a time when temperatures are expected to be in the 70 - 75º range for a few weeks.


Feeding artichokes

Artichokes are heavy feeders. Using a side dressing (adding fertilizer next to plants, where it is watered into the soil around the roots, rather than digging it in), each mature plant will need 1/10 of a pound of nitrogen at the beginning of the growing season. Plants will also benefit from 1 cup of ammonium sulfate and 2/3 cup of ammonium nitrate during the harvest season. If you are like me and prefer a more natural approach, simply keep mulching the area around each plant with aged compost.


Artichoke pests & diseases

Aphids and slugs are an artichoke’s most common pests. At the end of each growing season, many pests can be thwarted by cutting the stems to ground level and covering with mulch. Artichoke plume moths can be a problem in perennial beds. Artichoke curly dwarf is a viral disease that causes stunting and dark, necrotic (dead) spots. To avoid this problem, use only disease-free stock. Botrytis is a fungal disease that occurs after extended periods of warm, wet weather.


Harvest your artichokes when they are about the size of an apple for the best flavor and tenderness.


A funny side note about artichokes: the fleshy leaves contain a chemical, called cynarine, that inhibits certain taste receptors, making water and other things taste sweeter!

Spring is the time of year when it is common to see a white powder appear on the leaves of cucumber, melon and other cucurbits. You may also see it on tomatoes, roses, snapdragons, chrysanthemums, peas, artichoke, beets, grapes and practically everything else. This bane of gardeners is called powdery mildew.

What starts as a small white spot, powdery mildew expands to engulf an entire leaf as the nutrient-sucking fungi bleed the life from your garden. It can be found on either side of a leaf and sometimes on stems.


Powdery mildew is a fungus. It is caused by different types of fungi (e.g., Erysiphe spp., Sphaerotheca spp.), depending on which plant is affected. Contrary to common belief, moisture and humidity are not needed for these fungal beasties to appear.


Powdery mildew fungi simply need living plant tissue to survive and thrive. To make matters worse, their spores are carried on the wind, so the battle never ends. The reason powdery mildew seems to disappear in the heat of summer is that these microorganisms prefer shade and temperatures between 60° to 80°F. Our California summers are simply too hot for the spores to reproduce. Instead, they remain dormant until conditions improve.


The white powder seen on leaves is actually thin layers of fungal tissue (mycelium). Other symptoms of powdery mildew include:

• yellowing leaves
• leaf die off
• distorted leaves
• yellow patches on leaves (especially on tomatoes, peppers, onions and artichoke)

Not only does powdery mildew cause leaf loss, it can also weaken a plant. This lowers production and increases susceptibility to other pests and diseases, such as Citrus Blast. Leaf drop can also lead to sunburn damage.


Prevention and vigilance are the best ways to counteract powdery mildew. These tips can help, but nothing will eliminate powdery mildew in the garden:

• Plant resistant varieties
• Change the species of annual plantings to break the fungal life cycle
• Monitor plants for new spots of white mycelium and remove infested leaves
• Plant in sunny areas
• Provide good air circulation (use spacing and pruning)
• Avoid applying excess fertilizer
• Apply horticultural oil (not within 2  weeks of applying sulfur, or your plants will BURN)
• Apply Bordeaux mixture
• Apply sulphur products before symptoms appear (only when temperatures are below 90°F)
• Apply biological fungicide (not as effective as oil or sulphur)
• Apply fungicides, as a last resort

Now, some people recommend spraying plants with a baking soda and water spray. I have had mixed results, but other people swear by it.