When you purchase a pack of turnip seeds, they'll be surprisingly small. At just under two hundred thousand tiny seeds per pound, a very tiny packet will give lots of turnip shoots! Turnip grown in Southern England is known as 'turnip top', having larger and deeper roots that reach the damp earth below the ground. Turnip varieties used for recipes are generally smaller than the English variety, which has the distinction of having deeper green and yellow leaves, a longer lifespan, and a taste most chefs love - especially if it's seasoned with salt.
Whether or not to plant your Turnip seeds is entirely up to you. They're a fast growing perennial, so you should have no problem producing a crop each and every year, even in the depths of winter. In warm weather, turnip seeds germinate easily in full sun but need to have a back door planted through them if you want them to produce an early crop next spring. In cold weather, you'll need to plant them in a separate location, and protect them from frost by covering them with a plastic bag or tarp.
Planting conditions vary widely between different heirloom varieties. A common approach is to plant your Turnip seeds in a hole four feet deep and two feet wide and three feet away from the base of your favorite trees. Don't worry about compact planting mix as it shouldn't be compacted more than one inch deep. Your heirloom varieties do better in rocky areas, so you might consider planting them in sand. However, if you're planting them in rocky soil, try to choose heirloom varieties that grow well in rocky soil such as ashes, gravel, pebbles or slag, instead.
Most varieties prefer full sun exposure; however, some will tolerate partial shade. The majority of turnip seeds are self-sowing, so timing is everything. Planting them too soon will result in dry and cracked shoots. Planting them too late will result in them hardening up and losing their appetites before the plant has time to flower.
Full sun or partial shade tolerant Turnip seeds are extremely drought resistant but don't expect them to do well in dry soil. They do fine in medium moisture but they don't do well in dry soil. They also don't do well in flood-tolerant soil because their leaves can become tangled in the roots of weeds and clog pathways.
Keep in mind that turnip seeds are shallow rooted and will not do well in the acidic soil of a sloping site. Water your turnip plants carefully and keep them well watered until they bloom. You should water your turnip seeds just once a week in order for the roots to develop a firm root system and develop a strong hold on the soil for good root growth. If you leave them too long between waterings, the roots may die back which will result in your turnip seeds being scattered all over the place.
Fertilize your turnip seeds about a month prior to planting, especially in the spring. In fact, the soil should be so dry that you couldn't use any fertilizer when you were planting your turnip seeds. However, if you want your turnip plants to grow strong and healthy, use fertilizer as often as necessary throughout the growing season.
If you plan to harvest your Turnip seeds before planting them, there are a few considerations you need to keep in mind to ensure the best crop yield. Harvest them just after the flower buds open and just before they die back (the last stage of their dormancy). Keep an eye on the heirloom turnip varieties you choose to use and do not harvest just before the flower buds open. Also, while you are harvesting your turnip seeds keep the root system well watered. Once you have finished harvesting your turnip seeds you can put them in the vegetable garden and wait for the harvest to come in the following year.