Do you Soak Seeds Before Planting? | 8 Seeds you Should Soak

Just think… Someplace around the world there is probably someone sowing seeds right now; in another place, there is probably someone preparing their raised beds with organic matter ready for planting out in the spring.

Well, at the time of writing this, I am just about to start soaking some sunflower seeds ready for planting. Do you soak seeds before planting? If you do not soak seeds, maybe you should start; after all, you want to give your little babies the best start to life as you possibly can.

Not all seeds will require soaking although there are certainly several seed varieties both flower and vegetable that will benefit from it.

Soaking causes seeds to swell and the outer layer which is often hard, and shell-like will soften making it easier for the seeds to germinate therefore speeding up the process after sowing. Soaking seeds is a great way to give your plants a little jump-start and this is especially good if planting a little later than usual.  

How to Choose Seeds

Choosing the right seeds is important for many reasons. Poor quality seeds can lead to plants that are deformed with ill health and vegetables that do not produce well.

We like to save our own seeds from our previous years’ crop, but we recommend that as a beginner you buy them from a reputable source. It is important to buy good quality seeds for your garden that are more likely to be viable to avoid disappointment.

Good quality cultivars are usually F1 hybrids, meaning that the parent plants were specifically chosen and crossbred. These F1 hybrids are usually a little more expensive but they are worth the extra few pence as they are likely to be more vigorous and productive than standard seeds.

When buying seeds, make sure that you check their age as although the seeds for some plants and vegetables are said to be viable for many years, we advise not to purchase seeds that are older than 3 years.

Why Soak Seeds?

Seeds are soaked to break down their natural defences. Seeds by their very nature are designed to be tough. Their outer layer or shell is often waterproof, awfully hard, and sometimes almost impregnable which allows them to take quite a beating in the natural world.

In nature, seeds may have to withstand various challenges such as being eaten by wildlife or huge variations in temperature. They may have to cope with extreme frost in some of the harsher climates and even drought in others, but nature has found a way to let them survive whatever is thrown at them, so we like to give them a little helping hand to start their germination.

Soaking seeds allows the seed shell to soften and the embryo absorbs water although in some cases, just soaking seeds is not enough. Some seed casings are just too tough and almost completely waterproof. These usually larger and albeit tougher seeds could also do with scarification.

Seed Scarification

Tougher seeds that have extremely hard outer casings can often be unreliable and difficult to germinate so will benefit from scarification. Scarification is the process whereby the outer casing is intentionally damaged before soaking allowing the water past the hard outer barrier that is protecting the embryo.

How to Scarify Seeds

Scarification can be done in various ways although at Garden Doctor we have our preferred technique and that is by making a small nick in the seed casing. The nick must be extremely shallow and carefully placed to ensure that you do not damage the embryo inside.

Seeds will often have a flat spot or eye which is called a hilum. The hilum is the scar where the seed was originally attached to the ovary of the fruit. It is best to carefully nick your seed with a razor blade opposite this area to reduce the chance of damaging the embryo.

Another method of scarification that we sometimes use when scarifying larger seeds is to use sandpaper or a nail file. Again, you will want and wear down part of the outer casing opposite the hilum until you reach a depth that is likely to allow the seed to absorb water.

Scarified seeds will require planting straight away as they will not remain viable for long afterwards.

How to Soak Seeds

Although some methods vary slightly, all you need to soak your seeds is a small glass, some water, and your seeds.

1. You will need to take a small glass and fill it with warm water from the tap.
2. Carefully place your seeds into the water (some people even add a touch of vinegar or something a little acidic to the water to simulate passing through an animal’s stomach).
3. Leave for 8-10 hours (Overnight is best).
4. Plant your seeds first thing in the morning.

It really is that simple although you will need to be careful not to over-soak your seeds. 

Seeds can be left soaking for up to 24 hours, but we would not advise soaking for that long unless the seed packet specifically advises doing so. 

We just soak our seeds overnight allowing the seeds enough time to soak up some water but not too much time or they may drown.

What Types of Seeds need Soaking?

All seeds benefit from soaking although some seeds are extremely small and become difficult to work with once they have soaked. When exceedingly small seeds such as tomato or carrot seeds have become swollen and soft, they become very easily damaged but to be honest, these smaller seeds are usually fine without a soak.

There are various larger vegetable and flower seeds that have a hard outer casing that will benefit from a helping hand. They are seeds like sunflower, sweet pea, lupine, nasturtium, corn, pumpkin, bean, and squash.

Summary

Seeds are nature’s little battlers and they have evolved to be tough and hardy and able to cope with almost all weather conditions. Some seeds are so tough that they even struggle to germinate on their own and that is where we come in.

To give your seeds the best start in life, we recommend that you give them a soak to start off the growing season with a bang!

Garden Doctor Tips

“Check the next day’s weather before planting the seeds so you do not get too wet!”

“Scarify your seeds with a sharp razor blade on the opposite side to the hilum!”

“For best results and to increase the likelihood of your seed viability, we recommend buying F1 cultivars!”

“Check the date of your seeds and try and purchase seeds that are under 3 years old!”

Frequently Asked Questions

How long should seeds be soaked?

Seeds should be soaked overnight for approximately 8-10 hours. Some seed varieties can cope with being soaked longer but be sure to check your seed packet.

Can you over soak seeds?

Yes, seeds can be over-soaked. Seeds that are allowed to soak too long will drown and the seeds will no longer be able to germinate.

How do you scratch seeds?

You scratch seeds using a razor blade. Very carefully make a small incision on the opposite end of the hilum.

Is it best to soak seeds before planting?

Yes, all seeds will benefit from soaking although some smaller seeds do not really require it. Tomato seeds for example become very difficult to handle once they have swollen.

Do sunflower seeds need to be soaked before planting?

Yes, we recommend that sunflower seeds are scarified and then soaked overnight.

Is soaking lupin seeds necessary?

Soaking lupin seeds is not always necessary. Lupins are generally hardy plants, and the seeds can germinate well even without soaking. If you decide not to soak the seeds, ensure they are properly planted in well-prepared soil, providing adequate moisture and suitable growing conditions.

If you choose to soak the lupin seeds, place them in a container with room temperature water and let them soak for about 24 hours. After soaking, plant the seeds in moist soil and continue to provide appropriate care as they germinate and grow.

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