Plant Parenting: Optimum Temperatures for Seed Germination

January 24, 2020

Seed Germination Temperatures

It's that time of winter where many of you may be starting seeds indoors. Both air and soil temperature affect the speed and success rate of seed germination and growth. Each type of plant has a different optimal temperature range, based on its natural environment. Be sure to check the seed packet for specific optimal temperature ranges for germination.

Different types of seed will germinate faster than others. This basil ‘Genovese’ (below) is clearly an overachiever, when compared to the slower tomato and pepper seeds sown at the same time.

PC: Leslie F. Halleck

Many seeds germinate well in the 68°F to 80°F (20–26.6°C) range for both soil and air temperature. If temperatures are too cold or too warm, some seeds take a very long time to germinate or may not germinate at all.

If you want to speed up germination, or are starting seeds in a cold room or garage, try using a seedling heat mat, that goes under your seedling tray. Seedling heat mats can warm the soil or growing media temperature about 10-15°F. You can also purchase controllable thermometers for your heat mats.


Plant Parenting: Tips for Avoiding Damping Off in Seedlings

January 17, 2020

Damping Off Disease

Damping off is a disease that is extremely frustrating for seed starters. It's usually a combination of several soil borne pathogens that move in quickly to take down seedlings as they are germinating. If your young seedlings turn brown or black at the base of the stem, then topple over, your you see mold-like growth on your seedlings, damping off may have set in. Typically, properly managing and balancing moisture is the key to preventing damping off.

Dealing with Damping Off

There are a few tips you can employ to decrease your chances of the disease attacking your seedlings:

  • Avoid adding fertilizer to your seeds before or right after they germinate. Fertilizers can encourage fungus and mold growth.
  • Commercial growers will use synthetic chemicals to prevent damping off, but you probably don’t want to do this in your home or for edible crops. A handy alternative is to water your seedlings with a hydrogen peroxide solution. Hydrogen peroxide oxygenates the soil, which kills off many fungi and bacteria. Mix 1 teaspoon of hydrogen peroxide to 2 cups of water and then use the solution to water or mist your seedlings.
  • Keeping excess water off the foliage will help reduce fungal disease problems. As seedlings grow, you’re best to shift from a spray bottle—which wets the foliage—to small watering cans or squirt bottles, so you can deliver water directly to the root zone without getting water on the foliage.
  • Don't leave your germination humidity dome on too long. Once seedlings have germinated and are developing true leaves, you can usually remove the humidity dome so excess moisture doesn't build up and breed disease.

Plant Parenting: How to Recognize Damping Off in Seedlings

January 10, 2020

Damping Off Disease

Nothing is more frustrating than to have your seemingly healthy seedlings suddenly succumb to disease. Damping off is a fungal disease caused by a combination of pathogens: Rhizoctonia, Pythium, or Fusarium fungi.

While older seedlings and transplants can typically fend off the fungi, germinating seeds and young seedlings are particularly susceptible.

Conditions were too wet and dark when these microgreen seedlings were beginning to germinate, and some mold began to grow on the seeds. I removed the humidity dome for a day or two and increased the light and was able to save this crop.
PC: Leslie F. Halleck

Recognize Damping Off

Signs your seedlings are suffering from damping off:

  • Your seeds never emerge from the soil
  • The cotyledons are discolored or look waterlogged or mushy
  • The seedling stem becomes thin and water-soaked looking
  • The new leaves wilt or look discolored
  • You find no roots on your seedling or the roots are discolored and stunted
  • White mold-like growth develops on seeds or seedlings in high humidity


Plant Parenting: Use Silicone Molds for Propagation

December 17, 2019

Reusable Plant Propagation Containers

If you're like me, you're probably always looking for ways to recycle materials we already have around the house for our plant projects. I try very hard to cut back on plastic use in as many areas of my life as I can, and try to use re-usable containers whenever possible. Same goes for my plant propagation projects.

PC: Leslie F. Halleck

For example, I’ve found that silicone molds - as shown above -make handy seed and plant cutting trays. You might have some of these silicone molds for making ice, soaps, or baking. They are pretty great and last a long time. When you start seeds or cuttings in them, the plugs pop right of the malleable container cells after they are rooted.

Containers with no drainage

Now, as they come these molds do not offer your seedlings or cuttings any drainage. So you'll need to be careful not to overwater. This is actually an advantage when you you are rooting vegetative cuttings, because they need to stay very moist. You can simply stuff these mold cells with some sphagnum moss and you're good to go. If you are starting seeds in them, be very careful with water, OR poke some drainage holes in the bottom of the cells if you know you're going to keep using them for seeding.


Plant Parenting: Holiday Gift Guide for Plant Lovers!

November 26, 2019

Gifts for Plant Geeks

I'm admittedly not a huge shopper come holiday season...trying to find just the right thing for everyone stresses me out! BUT, when it comes to my plant keeping and indoor and gardening hobbies, I can always tell you what I'd like. This is the time of year I start getting questions about cool plant tools. As a professional horticulturist in the industry - and a lifelong gardener and indoor grower, I use A LOT of gear and always get to see what items are brand new to the market. I thought I'd show you some of my favorite items right now if you happen to shopping for a plant lover in your life.

Please note, this is not a sponsored post or advertorial. These are all items I personally like and use that I'm sharing with you!

Mini Bamboo Light Garden, Gardeners Supply Company

Not tool long ago, I acquired the low and medium LED Bamboo Light Gardens Gardener's Supply Company, which I love. But they recently came out with a Mini version, which will fit more easily under cabinets or in smaller spaces such as college dorm rooms, studio apartments, or any other setting where space is at a premium. The Mini will be great for keeping small houseplants and succulents alive and thriving indoors as well as some indoor herbs. The nice thing about these plant light shelves is that they look like a piece of furniture, instead of a utility item. You know me, I don't like to sacrifice style when it comes to my plant growing gear!


Golden Plant Stakes from BOTANOPIA

Once your baby houseplants start to grow and vine, you may quickly find yourself needing a stylish way to support them. These lovely plant stakes and supports from Botanopia can be used in potted houseplants and outdoors in patio pots or the garden. Great for all those hoya you're collecting. And I love the chain support for your climbing Monstera! If you have a copy of my book Plant Parenting, this is the company I ordered all those lovely ceramic propagation supports you see me use with my glass jars. They used to be called Sprout, but recently changed their name to Botanopia. Lovely stuff.


Green Thumb Starter Kit from Soltech Solutions

If you've read my book Gardening Under Lights - or listened to any of my grow light podcast interviews - you probably know that I'm a fan of the SolTech Solutions Aspect LED grow lamps. Designed to both please your plants and style your space, the Green Thumb Starter Kit is the perfect living wall starter-pack for any plant lover. With the pop of the WallyGro planters, the warm brilliance of the Aspect and the Pinocchio wall hanger to tie it all together, your plants and home will be looking and feeling happier than ever. They have a nice deal going on this combo kit right now!

Also, because the guys at SolTech are super nice (and they like my book Gardening Under Lights) they gave me a discount code you can use anytime you order to receive 15% off! Just use: halleck15


Folding Watering Can from Centurion

I don't know about you but finding places to stash large watering cans is always a challenge. Again, I don't like to sacrifice style for function in my living space, so where to put a large two-gallon watering can?

THIS folding watering can is for the gardener who doesn't have much storage space - perfect stocking stuffer for those with small spaces and lots of plants. I was seriously impressed with how flat this watering can folds and the large volume of water it holds. The folding watering spout is great because it keeps you from splooshing water all over the house as you travel from plant to plant. Once empty it returns to flat, perfect for tucking under the sink (or the garden shed).


Forest Green Planner from Passion Planner

I’ve been using Passion Planners for a few years now and I find them very effective. Us plant lovers get a bonus for the 2020 planning year with this leafy green version, complete with embossed Monstera leaves! I already have mine! I usually use the large planner, but switched to a small planner this year so it was easier to take with me on all my work trips.


Garden in a Box with 17″ Procyon Light from Happy Leaf

If you're looking for a good under-cabinet growing set up for small greens, herbs, and microgreens this is a great kit to start with. This kit comes complete with 17” Procyon LED Grow light along with growing baskets, hydroton, nutrients, and lettuce seeds that you can get started with for some passive hydroponics growing. I just grabbed some of my empty mason jars and set up the system in a few minutes, and my baby lettuce is growing on nicely. Very cute. I really the hooks that screw into the top of the LED lamp, make it really easy for you to either hard mount, or hang it from any hooks.

The 17" Procyon LED produces mixes blue and red diodes with full spectrum white diodes, so there is still a slight pinkish tint to the light, but it's not super pink, like most dual-band LEDs, so it won't be offensive in your kitchen or office. It will also be good for growing your high light succulents indoors with some supplemental light from nearby windows. Hang the lamp closer to high light plants, higher for leafy greens. Check out the 33" Procyon, which puts off less pink light (it blends green diodes with the blue/red). Great light volume output for a larger footprint of houseplants, succulents, or leaf greens and microgreens.

I've measured the PAR output on these LEDs and they emit just the right volume of light for the necessary DLI for the lettuce they include with the kit - (when you run the lamp for 11-12 hours max for lettuce so it doesn't bolt). If you set the system up next to a bring window, you can run the lamps for fewer hours.


Plant Lady Sweatshirt from Bloom and Grow Radio

If your plant lover wants to garden in plant-style while it’s chilly, be sure to grab your Plant Lady sweatshirt from my gal pal Maria over at Bloom & Grow Radio. I mean, why not advertise your plant insanity to the world? It’s always best to give everyone a warning that they are going to have to listen to you talk about plants. I think these are also on sale right now. And don’t miss my next episode with Maria all about Roots 101! It debuts 12/4/19. Plus, be sure to catch my other episodes on the basics of natural light for your houseplants and how to measure light, propagation 101, and grow lights 101.


BloemBagz Herb Planter from Bloem Living

If you're looking for easy ways to pot up herbs - or any smaller plants really - and want something that stores easy, I love these BloemBagz. Their herb planter is designed with herbs in mind. It comes in two sizes: the big herb planter has six pockets, and the mini herb planter has three. Each one has a large top space for planting taller herbs. The small planter also has grommets at the top for optional hanging or attaching them to railings or a balcony. Lots of nice color options to choose from - bright to neutral. Great stocking stuffer.


Hooray for Haworthia! Bundle from Little Prince of Oregon

BUY PLANTS! Of course. But from where and which ones? There are lots of places I like to order plants so it's hard to choose just one. Succulents are ever so popular, but most require a lot more light that we typically give them indoors. If you have a houseplant collector who hasn't yet jumped into grow lights, then Haworthia are the low-light succulent for them. Little Prince has the perfect bundle of six lovely Haworthia species, perfect for lower light levels. They also have some cute pottery you can pair them up with.


SpotOn PAR Quantum Light Meter from Innoquest

Ok, so if you have a serious indoor grower in your life, or a houseplant addict who is adamant about getting the light right for their burgeoning plant collection, then I have a new PAR light meter for you to check out. This SpotOn PAR meter is quite easy to use, is calibrated to take accurate PAR measurements from LEDs (as well as natural light and all your other type of grow lamps), and has an easy DLI scan option. I also like the handy little stake that's attached, which allows you to stick it in a plant pot. Quality Quantum Flux PAR meters aren't cheap - they will usually run you at least in the $400-$500 range and higher, depending on features. The SpotOn takes a little price heat off at $295 - perfect for that REALLY NICE gift for the serious plant lover in your life.

GIVEAWAY ALERT: I asked Innoquest if they'd be willing to provide one of their light meters to include in a holiday book giveaway I'll be doing next week (12/4)..and they said YES! SO, keep your eye's peeled on my Instagram channel @lesliehalleck for that very cool giveaway post. I'll be giving away a package that includes signed copies of my both my books, Gardening Under Light and Plant Parenting, and one of these SpotOn PAR Meters.


My Book Bundle!

Of course, I'd be remiss if I didn't include my own books on my gift list! My book Gardening Under Lights came out last year - it covers all the basics of the science of how plants use light, descriptions of all the types of grow lights you can use and how they work (which ones to use), how to accurately measure light and calculate your plants needs, and how to grow a variety of ornamentals and edibles indoors. I cover environmental control, grow tents...you name it.

My NEW book Plant Parenting just came out this summer, and covers all things plant propagation! I teach you all the basics of how to propagate plants in many different ways, with tons of instructive photographs for you to follow. Houseplants, veggies, and flowers.

So if you need them for yourself, or the plant lover in your life, you can get my book bundle of both books for a special price - personalized and signed by me. You can also purchase them individually in my SHOP.


Hard Freeze: Should I Cover My Plants?

November 9, 2019

Cover plants in a freeze

Hard freezes have come early in North Texas, and we're headed for another one come Monday night/Tuesday morning (11/11), with temps predicted to be in the 26F-31F range. I often get questions about what and when to cover plants, so I thought I'd share an answer I just provided to a client yesterday.

This time if year, you may have a mix of newly planted cool-seasons plants, such as pansies, violas, kale and mums, along with some summer leftovers such as croton. You may also have young cool season veggie plants in the garden.

Pansies and violas cold hardy and typically just fine at temperatures down to the mid-20s without protection. so I usually don't recommend you need to cover them at those temperatures. Same goes for kale and cabbage. Violas are generally a little more cold tolerant and resilient than pansies. Pansies and violas are still hardy down into the mid teens, but you'll lose some flowers or flowers buds once you get down into the low 20s or high teens, depending on where they are planted (how exposed versus close to a house or under tree cover).

Your mum plants will survive but their flowers will probably be burned in the freeze.

It's always best to water things in before a hard freeze which will help increase turgidity in the plants, helping to protect them from cold damage.


Veggies & Warm Season Color

If your cool season veggie plants are very young or are seedlings, you should cover them if we drop down to the mid-20s. Otherwise they will usually be fine at temps above that. You'll often see plants such as kale and mustard greens be frozen solid, then perk right back up once the sun comes out.Crops such as spinach are very cold hardy and never require covering in our area.

Some cool-season color, such as cyclamen, is a bit more marginal in it's cold hardiness. If you've recently planted cyclamen, you should go ahead and cover them on Monday. Same goes for primrose or Gerber daisy. Diascia, cherianthus and the like should be fine uncovered, however you could lose some flower buds.

If you have Camellias with new flower buds developing on them, you should go ahead and cover them. It's a pretty typical scenario in this area for camellia buds to be nipped off in early freezes, or by a frost that arrives during a warm spell. Summer tropicals such as croton are not frost hardy. These and any other warm season annuals probably won't make it through the frost, however if we only get to 29F, and you cover them properly, they can survive.

Frost Cloth

The goal with covering plants is to insulate them by creating some warmer air around the plants. So the frost cloth should not be tight on the plants or be pressing them down or against them - or wrapped tightly around them in pots - you lose the insulation value you when you do that.

You need to cover the plants with some slack, or even prop up the frost cloth, but make sure it's tightly secured down at the base around the perimeter, or take it all the way down to the bottom of a raised bed or container. If the frost cloth is just wrapped tightly around the plant, but it's not secured at the base (meaning air can just flow up into the frost cloth at the base of the plants) then the plants are not protected. And that there are no open holes or gaps in overlapping fabric where air can blow through.

Note that you'll get on average about 4-5 F degrees of temperature protection from typical frost cloth - you can double layer it to improve that, or buy heavier frost cloth that is rated for 8-10F protection.

Sometimes temperatures take a hard dive below what is forecast. In such situations even frost cloth won't always do the trick; especially if it's been on the warmer side, then temps all of a sudden get cold. When there are sudden big shifts in temperature, plants don't always have time to acclimate and you may lose plants that are typically cold hardy in our area.

Don't use plastic to cover your plants. Where it touches the foliage it can actually do damage in the cold. You can use blankets and sheets, but remember you're trying to create a warmer air pocket around the plant. Heavy blankets and sheets will provide some protection, but only if they go all the way down to the ground around the plant.

Ice & Snow

If there is heavy ice or snow, know that even if your plants are covered with frost cloth they won't necessarily be protected the same way. When the ice or snow weighs down the cloth and presses against the plants, they can still be damaged. In fact, that can cause even more damage to the plants than if they were not covered. That said, if your plants are not covered and they get covered with a thin coating of ice, they may be just fine, as the ice can actually act as an insulator. But it all depends on the species of plant and it's temperature tolerance.


Backyard Chicken Stories: Hawk Attack!

November 4, 2019

Backyard Chicken Stories

A friend of mine just lost one of her chickens last night and it made me think about all the girls I've kept, and lost, over the years. It might seem silly to some to get attached to a chicken, but if you've never kept chickens you may not realize how full of individual personality they are. Nor how connected to you as their caretaker they can become.

One of the most important things you learn when you start keeping livestock - even if it's in the city - is that you must become an expert on their health and wellness. You are their first line of defense, so you end up studying all sorts of bird illnesses and their symptoms and causes. You have to monitor your birds closely and learn to recognize conditions, whether they be pests, diseases, injury, predator, or flock dynamic issues. You'll learn to administer medications, treat wounds, and be responsible for putting down the animals humanely. In fact, when teaching chicken keeping classes, I'd always advise that if you aren't willing to put a chicken down humanely yourself, you may not be ready for a flock. When it comes to chickens, you can't really just run them to the vet down the street. Most city vets don't treat chickens and aren't terribly familiar with their ailments. You are front line triage.

Often, you can't save your chicken once it succumbs to something like a virus, bacterial infection, being egg bound, or any other number of injuries. But every once in a while, you get lucky. My favorite chicken triage story is one about my black laced silver wyandotte, Kim Deal. That's her on the left in the photo, which is from 2012 Dallas Observer story titled: "The Chicken Quixote". The barred rock on the right is Joan Jett.

you KD!

Me, Kim Deal & Joan Jett
PC: Dallas Observer

We live near a small urban lake, White Rock Lake, in Dallas where many, many birds live and use a migration stop. So we have LOTS of hawks. Hawks love chicken, and they are the most serious predator for our flock. One day I heard some urgent alert squawks coming from the chicken yard. My husband opened the patio door and said "hawk in the coop!!!" Without even thinking I bolted out the door and threw the chicken yard gate open, coming face to face with a huge, mid-flight hawk, who was already trying to make a meal out of Kim Deal. Talons outstretched, the hawk flapped its wings in my face while I yelled at it to bugger off. According to my husband, it was quite the scene.

Once the hawk decided dealing with me was not worth lunch, it flew off and I turned to inspect the carnage. The hawk had gotten a hold of KD a couple of times but they looks of it, but couldn't manage to fully gut her or carry her off. But the hawk had managed to slice multiple large gashes into KD's skin, down to the muscle tissue. This was not good.

Again, without thinking, I yelled at my husband to go get me the BluKote and super glue. I then proceeded to quickly disinfect her wounds - of which there were many - and super-glued all of her gashes closed. Yep, superglue. This is, of course, the original purpose of the product, so why not? I figured if she had any chance of survival, this was the best option. Kim Deal spent about three days in the roost, head hung a bit low. Clearly, and understandably, she didn't feel great. But surprisingly, by the next week she had bounced back and lived another good 2.5 years of chicken life, and egg laying. Crazy. 7 years later, Joan is still with us. My girls are hardcore.

We miss you KD!


Plant Parenting: Cut down on waste by making paper pots!

October 14, 2019

It's no secret that we all need to figure out ways to reduce our use of plastic.

Like it or not, there's a LOT of plastic that gets used in everyday gardening activities - especially propagation and growing. If you're looking to ditch some of the plastic pots you use to start your seedlings and cuttings, consider making your own paper pots!

Wooden paper pot maker
PC: Leslie F. Halleck

Paper pots are easy to make & they help cut down on all sorts of gardening-related plastic waste. Get yourself a wooden pot maker then grab the newspaper.

PC: Leslie F. Halleck

Wrap the paper around around the pot maker handle, and tuck under the bottom edges. A piece of paper around 3" x 10" works best with minimal waste.

Paper pots perfect for seedlings
PC: Leslie F. Halleck

Learn more about paper pots, and other ways to minimize waste when propagating, in my book "Plant Parenting: Easy Ways to Make More Houseplants, Vegetables, and Flowers".


Back to top

Tips in your inbox

E-Newsletter

Sign up for the E-Newsletter for my latest green industry updates for pros + plant and gardening tips for home hobbyists.