Oregano: Tender perennials to about 45cm. There are several varieties. Oregano has sprawling stems and may reach 60cm in height. It has clusters of small, pinkish-purple flowers.Sow seeds in spring, or divide established plants in late summer. Seeds may be slow to germinate  ideal temperature is 20C. Grow in light, fairly rich, well-drained soil with pH 7.0-8.0. After flowering trim the plant to prevent it from becoming straggly. Before the plant dies in the winter, cut back the year's growth to within 7-8cm of the ground. During the winter they need to be mulched heavily in very cold regions. Prefers full sun. Marjoram may be grown in containers but do not allow to become too moist. Some varieties can become quite invasive. All Oreganos grow better in full sun and well-limed, fertile soil that is moist. They will tolerate poor soil and dry conditions, but will not do as well. Good companion plant for cauliflower, but do not plant near broccoli or cabbage.

Marjoram: is a half-hardy perennial grown as an annual in regions where winters are cold. Sweet Marjoram is a little grey-green plant that will grow up to 30cm high if grown as an annual and up to 60cm high as a perennial. Branches that hang down will take root and grow to form a loose, airy clump. The small, rounded leaves have a unique sweet scent when crushed. They are used as flavouring, in sachets and as a source of oil in perfume. Sweet Marjoram produces unnoticeable white flowers. It has a tidier growth habit and a less robust flavour than Oregano. Marjoram is slow to grow from seeds, so propagate by dividing old plants. Harvest stems and leaves before flowering and hang to dry in small bunches. Cut back to 3-6cm. Good companion plant for eggplant, pumpkin and zucchini. In severe winters, pot up the roots and winter indoors. When the seed pods are brown, remove them from the plant. The seeds are difficult to locate, but worth the trouble of finding if you wish to grow a number of plants.

Hint for sowing tiny seeds: Poke a hole in one side of the lid of any glass jar. Put some clean sand into the jar and a handful or so of the seeds. Shake to mix. Then prepare a drill (furrow) in the garden bed, and walk along the drill, pouring in the sand mixture from the jar's pouring 'spout' as you go. No need to cover any further. This helps to spread the seeds more evenly and provides them with a light growing medium to get started. You can of course do this in miniature just by mixing the sand and seeds together and pouring it out using the slightly clenched palm of the hand as your 'pourer'.

Sun and patience.

Do you already have your seeds? Neither will be hardy in your zone... My advice would be to grow a sweet marjoram ("Max" is an EXCELLENT cultivar for potted production) and Mexican oregano (an upright-growing taste-a-like that's a fine substitute) in pots, and leave them outside while the weather's nice.

Thanks for all the info. I've started the seeds and have tiny (maybe a centimeter tall) marjoram and oregano seedlings inside. I won't put them in the garden until the beginning of June. I seem to be losing the tinier seedlings that sprouted for no particular reason. They don't seem overcrowded for how tiny they are. They are in a sunny window. The soil is a mix of Miracle Gro potting soil and peat moss. The soil is damp but not soggy. No signs of damping off.

Sweet marjoram is a wonderful salad herb and grows easily during warm weather. I've tried overwintering it with mixed success; it needs cool but not freezing winter weather and humidity, conditions that are hard to provide without a "cool greenhouse." You might be better off freezing the last harvest and growing it as an annual, or trying some of both.

I always thought oregano was a hardy perennial, but it hasn't come back for me. Have others in cold climates found that it survives the winter?

Well, my Greek oregano (Richters seed) stayed green all winter up to about 2 inches off the ground. It's supposed to be hardy for zone 5 and up.

It's hardy here too.

Vera