Transplanting Basics

 At this point you probably have weeks of time invested into your seedlings. You’ve made sure they had enough light, water, and nutrients to thrive, you’ve hardened them off, prepped your seedling beds, and now you’re ready to plant them. Don’t ruin all those weeks of work by using poor transplanting habits. Some plants are more frost/cold tolerant than others, and you’ll want to take that into consideration when putting those seedlings outdoors. Some seedlings, like those of peppers, cucumbers and squashes, eggplants and tomatoes can easily be damaged by frosts. While others like broccoli, cabbage, cauliflower and brussel sprout seedlings can handle some degree of frost and are less likely to be damaged. And don’t forget to get your peas, chards and kale direct seeded if you haven’t already done it! They can also handle some degree of frost and will be perfectly happy in the cooler days (if we have any left this spring).

Newly transplanted squash

When transplanting make sure that the seedlings are well watered before planting. Transplanting is incredibly stressful, and you want to make this transition as easy as possible for them. Stressed plants/seedlings are more susceptible to diseases and environmental conditions (cold, heat, water loss) so try to keep them happy.

Support the stem and try not to pull on it - pulling can damage it

Before you transplant anything you should have a master plan. Having a predefined plan of where each plant is going will help maximize your space, and later in the season can help reduce your diseases.  After you’ve figured out where everything is going then we can start planting. Determine the spacing you want your plants to be. Your seed packets have recommended spacings that should guide you in this. First make a hole in the soil where you are going to put your plant. Then gently loosen the plant from the pot by pushing the root ball from the bottom of the pot. 

Never pull a plant out of the pot by the stem or leaves. Place the seedling into the hole in the ground you’ve already made and place it so the potting mix is slightly (~1/4”) below the soil line. Then use the surrounding soil it to make it level. Potting mix is lighter and has less organic matter than most soil. This means that it dries out much quicker. By covering the top of the potting mix with a layer of soil you protect it from drying out too quickly. After you’ve completed your transplanting it’s time to water everything. Give the seedlings a good solid soaking, this will promote root growth deep into the soil, and ease the shock of transplanting. 

D. Hulbert (MSU Entomologist) helps move soil to level the planting

Especially early during the season frosts can still be a danger. Don't let all the hard work go to waste by letting the freeze. In the Lansing area our final frost date is June 15th! Remember sheets, tarps and blankets can protect those perky plants from deadly frosts. Just be sure to check the weather each evening. 

(Kansas State University) http://www.hfrr.ksu.edu/doc1793.ashx 

(Purdue) (http://www.hort.purdue.edu/ext/HO-66.pdf)

Friends help friends germinate

So this week's post is on proper transplanting. Since it isn't quite ready to be posted though, I decided to share a fun piece of gardening science that just came out this week. This is from a scientific paper published by Monica Gagliano and Michael Renton in the open access (which means anyone can access it) journal BMC. In case you don't want to read the full story, here is the synopsis: some plant species promote the germination of other plant species. That's right, planting certain species together might actually improve your germination. 

Garden lore and tradition is full of tips and tricks, but isn't it nice to know there is more than tradition and lore to some of these things? In this study, the authors looked at the germination of chile peppers when planted with chile peppers and basil. Surprisingly, pepper seeds germinated better when a basil plant was planted near them. Chile peppers also germinated slightly better when adult pepper plants were nearby.

This work was all done in a controlled environment (e.g. not a garden plot), but as the authors say, this validates claims by gardeners that basil helps chile peppers grow better. It might be a little late for this year, but this gardener is definitely going to give it a shot with her basil and chiles.

Hardening Seedlings off

If you haven’t already started, it’s time to start hardening off those seedlings. The days are getting warm and evenings are pretty mild. Hardening off (if done properly) takes several days to complete. Start slowly. While it’s tempting to rush outside and soak up every inch of sun, that is the quickest way to end up with a nice red burn (or sunstroke). Just like you need to get used to the warm weather and sunshine, so do your seedlings. These seedlings have no experience with direct sun, wind, varying temperatures and drying soil.

Seedlings in their trays, ready to be hardened off

On a mild day, take your seedlings outside in a sheltered spot and leave them for 2-3 hours. If you don’t have a good shelter you can cover your seedlings with a shade cloth or a milk crate. Something with holes to allow filtered light, wind to pass through is best. After that time bring them back indoors. As you increase the time they are outside, start moving them into direct sunlight. This will slowly get them used to direct sunlight, wind and variable temperatures. Continue this process for about a week. Water availability is another stress your seedlings have no experience with. Up to this point your seedlings have been watered regularly, not too much and never too little. When hardening the seedings off, go ahead and start reducing the frequency of your waterings. Never let your seedlings severely wilt, but allow them to dry periodically. This will cause their roots to grow deeper looking for more water.

So why do this? Hardening off your seedlings forces them to grow a thicker cuticle (a waxy outer covering which will reduce water loss), grow more vigorous root systems, and thicker stems (which reduces lodging due to wind). The idea is to give them just a little bit of stress to force change, without causing them permanent damage. The plants should also turn a nice dark green during this time as they produce more chlorophyll to protect against the sun.

Nice dark green leaves of the zucchini after living outside for a week.

Be aware, even properly hardened seedlings can still be damaged by cool temperatures. Warm weather crops like peppers and eggplants can be damaged by night temperatures below 60 °F. Cool weather crops can handle colder temperatures, and eventually can handle light frosts. If a frost is expected, and you don’t want to bring them indoors, cover them with a sheet. The sheet provides a protection that helps keep a layer of warm air around the seedlings, preventing frost from forming. 

Another thing to watch for is bleaching. This is when the leaves of the plant turn white in response to sun damage. You turn red; your plants turn white as the chlorophyll dies. In a nutshell, there is more intense light than the plant can photosynthesize. So in response, the plant reduces its ability to undergo photosynthesis. This results in damage to the chloroplasts (those little organelles that make plants green). Without chloroplasts, there is no chlorophyll and the plant turns white.

As always, this post was based on both personal experience and these helpful references:

http://gardening.wsu.edu/library/vege003/vege003.htm

http://www.coopext.colostate.edu/TRA/PLANTS/hardenof.shtml

http://www.uidaho.edu/~/media/Files/Extension/Bonner/ExtensionSpotlight/30HardeningOff%20Plants.ashx

Adamska, I ELIPs - Light-induced stress proteins: Physiologia Plantarum 1997. 100:795-805