You should water turnips with about 1 inch (2.5 cm) of water per week from rain or your garden hose. This steady amount keeps the roots growing smooth and tender all through the season. Too little water makes them bitter and woody, while too much causes rot. Getting this balance right is the single biggest factor in growing great turnips at home. Nail your watering and the rest of the growing process gets much easier on you.
Turnip water requirements are strict if you want good roots at harvest. UMN Extension notes that dry spells can make turnips bitter or woody. Water helps root cells grow bigger each day. When you skip a week and then flood the bed, the root grows in uneven spurts. You end up with tough, stringy spots mixed with tender ones. Keeping your water supply steady each week stops this from happening and gives you smooth roots.
When I first started growing turnips, I thought my sprinkler was giving the plants plenty of water each week. Then I put a cheap rain gauge next to the bed and the truth came out fast. A 30-minute session was only putting down about half an inch of water. I had to run it twice a week just to hit that 1-inch target. That one small tool saved me from a whole season of bitter roots and woody texture.
How much water do turnips need in different soil types? That depends on what your ground is made of. Sandy soil drains fast, so you need to water 2-3 times per week in smaller amounts. Clay soil holds water much longer but can drown roots if you overdo it. Loamy soil sits right in the sweet spot and needs just one good soak per week in most weather. Know your soil type and adjust your approach to match what the ground can hold between waterings.
Drip lines or soaker hoses work best when you water turnips because they deliver moisture right to the soil surface. Overhead sprinklers waste water and keep the leaves wet for too long. Wet leaves invite fungal disease that can spread fast through your whole bed. In my experience, switching to a soaker hose two years ago made my leaf rot problems go away that same season. I won't go back to sprinklers for root crops now.
You should water turnips in the early morning before the heat of the day sets in. This gives the soil time to soak up every drop before the sun starts pulling moisture back out. Morning watering also means any splash on the leaves dries off fast in the breeze. This small timing change cuts your disease risk by a lot during the growing season. Evening watering leaves the soil wet overnight, which is a recipe for root rot and fungal problems.
Use the finger test to check if you need to water turnips between your normal sessions. Push your finger 1 inch down into the soil near the base of a plant. If the soil feels dry at that depth, give your turnips a drink right away. If it still feels damp, wait another day or two before the next round. This takes 5 seconds and tells you more than any set schedule ever will about what your plants need right now. Trust your finger over any calendar if you want to get the moisture level right for healthy, tender roots all season long.
Read the full article: Growing Turnips: A Step-by-Step Plan
