Written by Adam Boddy Date Posted: 29 January 2016
It's one of the most common issues you run into when starting plants from seed. What do you do when your seedlings grow skinny, delicate and spindly? This article can help diagnose why you are winding up with leggy seedlings and how to correct the problem.
What are leggy seedlings?
Leggy seedlings are those that become spindly, stretched and delicate instead of full and strong. These seedlings can be less vigorous and more prone to flopping over and failing to thrive. When these plants are transplanted later, they are likely to have problems. Stems that are too weak and thin can mean plants that are unable to stand up to outdoor weather conditions that include wind and rain.
Above: 'leggy' tomato seedlings. Seedlings are too tall and weak. White stems indicate lack of light.
Why do they occur?
The usual culprit for leggy seedlings is a lack of proper light. When seedlings are straining to get access to a light source, they can get tall too quickly reaching out for the light. But, this is not always the cause sometimes other factors can be to blame:
Poor soil conditions can cause seedlings to grow with slim and weak stems or when the soil is allowed to get too dry between waterings, it can keep the plants from leafing out as they should.
Temperatures that are too high can also lead to leggy seedlings. High temperatures cause a spurt of rapid growth in the stems, with leaves that fail to keep up.
Above: Seedlings straining for light by a window.
Can they be saved (and is it worth it)?
Disappointment can cause you to want to abandon weak seedlings and start over. But, it is often possible to correct the issues affecting your plants and get them moving toward stronger growth.
When light is the issue, changing the lighting conditions can often be all that is needed. Seedlings straining toward a window should be turned once daily so that the plants grow straight up and do not lean to one side. If there is simply not enough light for the plants overall, moving to a better lit area, such as a different window, an outdoor location or a greenhouse can remedy the issue.
Above: Brassica and tomato seedlings by a garage windowsill.
Moving plants to a cooler area can help if your seedlings are shooting up too quickly because of heat.
Sometimes, the issues that occur during the early seedling phases can be remedied when you transplant the seedlings to your garden. For instance when moving tomatoes, eggplant or peppers to the soil outside, plant them deeper than you normally would covering the majority of the stretched stem. This will encourage them to grow new roots along the buried part of the stem. This will not work for plants in most other families, however, as the stems may rot when buried too deep.
When determining whether to abandon or save leggy seedlings a few things to consider are:
-Do you have or can you get more seed?
-How much time have you already put into them? If it's only been a week since you sowed the seeds it is probably easier to just start again in better conditions. If it's been longer than a few weeks it's probably worth your while to try and save them, you've already invested your time and it would be a shame to have to start from scratch again.
-How leggy are they? If your seedlings are really leggy they may be too far gone and the chances of saving them may be slim. There is no harm in trying to save them but be realistic it may be smarter to start over.
How to avoid leggy seedlings in the future.
The best way to avoid leggy seedlings is to choose a position to start your seeds that will encourage the best growth. If you are using a window for lighting, choose a window that receives maximum light, if you don’t have an appropriate window consider other options like a mini greenhouse.
The use of an oscillating fan to gently blow the seedlings can help simulate windy conditions outdoors. This can spur the plants to form thicker, more resilient stems.
Be observant when growing seedlings; the sooner you notice something isn’t right the easier it will be to correct and by doing what you can to get the strongest seedlings from the start, you can be assured of the greatest level of success when you get your plants outside and into your garden.
Above: Healthy Brassica seedlings
Related blog posts:
Author: The Seed Collection Pty Ltd Date Posted: 2 November 2019
One of the common problems home gardeners face when growing tomatoes is when seedlings become “leggy,” or too tall and spindly for perfect health. The article explains why this happens and offers an easy way to save your affected seedlings.
Author: Sarah Rasdall Date Posted: 16 December 2015
Knowing how to transplant seedlings from pots into your garden is an essential skill every gardener needs to know. This article details some keys points to make sure your seedlings get the best start possible in their new home.
Author: Sarah Rasdall Date Posted: 13 November 2015
Sowing seeds is the most miraculous part of the entire growing process. Watching a complete plant come alive from a tiny capsule is truly a magnificent journey. Here are some tips to ensure that you can relax and enjoy this miracle of nature.
Recent blog posts:
Author: The Seed Collection Pty Ltd Date Posted: 15 January 2020
Effective use of fertiliser is an essential technique for getting the most out of your garden and its plants. However, there's much more to it than opening a bottle of plant feed and spreading the contents liberally over the soil.
Author: The Seed Collection Pty Ltd Date Posted: 22 December 2019
Scale are common garden pests which can badly stunt a plant's growth, ruin its appearance, or even kill it off altogether. This article explains how to recognise scale, what kinds of damage they do, and how to keep their numbers under control.
Author: The Seed Collection Pty Ltd Date Posted: 17 December 2019
Not every gardener is blessed with a large plot of land to work their creative magic upon. However, a small garden needn’t limit your ambitions – you just need to put a little more thought and planning into your horticultural efforts.
Author: The Seed Collection Pty Ltd Date Posted: 16 December 2019
There's an almost infinite variety of flower shapes, sizes, & colours out there to grow, & distinguishing between them can be confusing. This article outlines terms used to describe flower types, helping you to know what to expect from every seed you sow.
Author: The Seed Collection Pty Ltd Date Posted: 11 December 2019
While flowers may be highly prized for their beauty & scent, their appeal to humans is only a sideshow that gardeners down the ages have taken advantage of. Flowers have a vital biological function and are more complicated than many people think.
View all blog posts
RE: Leggy Seedlings
By: Gillian Vance on 17 March 2016
I am really enjoying this series. Not only do you provide the best seed at the best price, you are giving out great information! Your seeds have been the most succesful out of all the seeds I have ever bought. Thank you for the great job you do!
RE: Leggy Seedlings
By: Adam Boddy on 17 March 2016
@ Gillian, Great to hear your enjoying the articles Gillian! And fantastic to hear you're having success with our seeds :-)
RE: Leggy Seedlings
By: Jane Way on 17 March 2016
I bought my first lot of seeds from you recently and the first of those have just sprouted...very exciting! I will take note of this article to help avoid leggy problems.
RE: Leggy Seedlings
By: Colin Deer on 17 March 2016
Thank you for your timely article on leggy seedlings. Our warm weather down south has sent my seedlings into overdrive. Now I have an answer. Cheers Colin.