In cultivating a plant, particular parts are developed for food. We can divide them into four groups.
Root crops on Root Days
Development in the root region is in radishes, swedes, sugar beet, beetroot, celeriac, carrot, scorzonera, etc. Potatoes and onions are included in this group too. These days produce good yields and top storage quality.
Development in the leaf realm is in the cabbage family, lettuce, spinach, lambs lettuce, endive, parsley, leafy herbs and fodder plants. Leaf days are suitable for sowing and tending these plants but not for harvesting and storage. For these (as well as harvesting of cabbage for sauerkraut) Fruit and Flower days are recommended.
Flower plants on Flower Days
These days are favourable for sowing and tending all kinds of flower plants but also for cultivating and spraying 501 on oil-bearing plants such as linseed, rape, sunflower, etc. Cut flowers have the strongest scent and remain fresh for longer if cut on Flower days, and the mother plant brings forth many new side shoots. If flowers for drying are harvested on Flower days they retain the most vivid colours. If cut on other days they soon lose their colour. Oil-bearing plants are best harvested on Flower days.
Fruit Plants on Fruit Days
To this category belong all those plants which have their ‘fruit’ in the realm of the seed such as beans, peas, lentils, soya, maize, tomatoes, cucumber, pumpkin, courgettes, but also cereals for summer and winter crops. Sowing oil-bearing plants brings the best yields of seeds. The best time for extraction of oil later on is on Flower days. To grow good seed, Leo days are particularly suitable. Fruit plants are best harvested on Fruit days. They promote a good quality of storage and support regeneration. If storing fruit additionally choose the time of the ascending Moon.
There is always some uncertainty as to which category some plants belong. Onions and beetroot give a somewhat similar yield when sown on Root and Leaf days, but the keeping quality is best from Root days. Kohlrabi and cauliflowers belong to Leaf days, as does Florence fennel. Broccoli is more beautiful and firmer when sown on Flower days
From: : “The Biodynamic Sowing and Planting Calendar 2007” by Maria & Matthias Thun published by Floris Books