Should I Soak My Seeds?
You’re getting ready to plant your seeds. You have your seed starting supplies ready to go. Containers, seed starting mix, water, and lights, but what about the seeds? You check your seed package and it says soak overnight before planting. But you’re ready to plant now, is it a big deal? Should you postpone everything while you soak them, or can you just stick them in the ground now and take your chances? Is it all just propaganda from the seed companies or does it really matter? Let’s talk about one of the big questions of planting season in your garden – should I pre-soak my seeds?
Why Pre-Soak Seeds?
Why would you pre-soak your seeds? Well, some seeds have very thick seed coats and soaking them for 12-24 hours before planting can give your seeds a jump start on sprouting. It can make it easier for them to split the seed coat. Some seeds can’t break through the seed coat without soaking or weakening the coat in some way. Other seeds may have germination inhibiting compounds on the seed coat that need to be soaked away. Increasing the chance of each seed sprouting can save you money. If you don’t have to plant as many seeds to get the number of seedlings you want,
Also, large seeds that dry out during storage like peas, beans, or corn can benefit from soaking to rehydrate the seed. Although the seeds will soak up water from the soil once they are planted, pre-soaking can speed up sprouting. It can make it more likely for more of your seeds to sprout. It can also give your seeds a reservoir of moisture. This will keep the seedling going if your watering is inconsistent or outdoor temperatures get too hot.
Why Not Pre-Soak Seeds?
Although it is necessary to soak some kinds and helpful to soak others, there are some seeds you may not want to pre-soak. Very small seeds can clump up when they are wet and become very difficult to plant evenly. Lettuce, some herbs, and some flower seeds that are meant to be scattered by the wind are not usually good candidates for soaking. How big is “big enough” for soaking is a judgement call. Some salad greens or root vegetables pre-soak just fine.
Another reason not to soak some seeds is that it can spread certain molds and funguses. Especially damping off, a fungus that can attack the sprout where it emerges from the soil and spread to kill the whole tray of seedlings. Planting seeds in cool wet soils, or getting seeds that carry the fungus can also encourage damping off. If you keep a clean seed starting area and get your seeds from a reputable company, the danger of presoaking should be minimized for most larger seeds.
Seeds You Should Always Pre-Soak
Most medium to large sized vegetable seeds could benefit from pre-soaking. Peas, beans, corn, cucumbers, pumpkins, and other squash all need to be rehydrated or have tough outer seed coats. Larger cool season plants from the brassica family like chard, kale, and beets can also be soaked. Some flower seeds like sunflowers, nasturtium, sweet pea, lupine, and canna lillies need some soaking time. This will make sure their hard outer seed coats will split more easily.
When you are soaking your seeds, use clean, warm water and soak for at least 8 hours up to about 24 hours. Once the seeds have soaked, they need to be planted out. Do not let them dry out again or they may not sprout. Don’t let your seeds soak for too long or you can drown the baby seedlings. If you can’t plant them immediately after soaking, drain the excess water and cover with a damp paper towel to keep them moist until you can plant later that same day.
Other Seed Prep to Consider
Some seeds have such a strong seed coat that you may need to do more than just soak them in water. You “scarify” the seed by intentionally damaging the seed coat just enough to allow soaking to let the water into the seed coat. Some wildflower or tree seeds need scarification to encourage their seeds to sprout. You can use a nail file, sandpaper, or a small knife to make scratches just through the surface of the seed coat. Try not to damage the seed underneath. Then soak your seeds and plant.
Another kind of seed preparation is cold stratification. These seeds need a certain number of weeks or months of cold temperatures to trigger the seed to sprout. If you keep the seeds in a warm pantry all winter, they won’t be ready to sprout in the spring. Storing those seeds in a damp paper towel in your refrigerator crisper drawer can give them the conditions they need to encourage sprouting. Or, you can let them overwinter outside if you live in a cold climate.
There are lots of things for you to consider in preparing your seeds for sprouting. You need to soak, scarify or stratify some seeds to have the best chance of germinating. But other seeds might be fine straight out of the seed package. Do your research and plan ahead so your seed starting goes smoothly.
Looking for more information on starting your garden plants from seed? Check out my blog post How to Create the Perfect Seed Starting Setup for all the details on starting your plants off right.
Need help getting your plants all the way from seed to harvest? Check out the Mission: Healthy Plants course with everything you need to keep your garden plants healthy and strong.
