The waiting is the hardest part: Hardening off seedlings

I have three weeks to go until our average last frost date.

coldframe full

I did really well this winter, getting seeds sown and potting things on. Now, I’ve got to hang on until the tender things are safe to plant. The cold frame is jammed full.

Hardening off seedlings, though, is too important a process to skip. I skipped it all the time until I built my cold frame–mostly because I didn’t want to spend half the morning bringing trays of plants in and out of the house–and my plants performed correspondingly poorly.

Hardening off is a process of gradually exposing seedlings and tender plants to larger temperature variations and stronger light levels than they experience indoors. The process produces slower, sturdier, more resilient growth, preparing plants for life in the open garden. Without a cold frame, gardeners place plants in a sheltered location outside–maybe in a shaded site, close to the warmth of the house–for a short period of time, lengthening the exposure to outside conditions every few days.

Using a cold frame–basically a tiny greenhouse–makes the process far less tedious. It’s not quite a matter of set-it-and-forget-it, but it frees up lots of the time and space other parts of life demand. My cold frame, which I constructed myself from recycled materials for about $30, faces south and backs up to my house. I start hardening off my seedlings in mid-February, when we begin to see a few 50-degree (10C) days. I start with the hardy perennials, then move in the hardy annuals. Tender plants come last. Space permitting, I sow vegetable seeds in flats directly in the cold frame.

During the first few days in the frame, I place plants on its south side so they sit in slight shadow from the frame’s front wall. They gradually move towards the back as more plants come in. On unusually warm days, I vent the cold frame by propping open the glass doors, made of discarded windows. This keeps the temperatures inside from getting too hot–such fragile plants can quickly dehydrate and die if the temperatures climb too high. Sometimes I’ll prop open the windows entirely, but cover the opening with a bit of horticultural fabric. This practice lets the light in but keeps hungry foraging birds and squirrels and early insect pests out.

coldframe full 2

The second quadrant of the cold frame.

We’re getting close enough to the last-frost date that I may move out some of the plants with the longest tenancy–particularly the perennials–into permanent locations. They’ve withstood some cold nights already, so a late frost won’t likely bother them.

Believe, gardeners! The digging season is nearly here.

 

 

 

Trash into treasure: Decorating with weeds

Holiday decorations from the garden delight me in ways other ornaments can’t. I’d rather have pots of forced bulbs, a Christmas cactus, or fresh garlands of mixed greenery than anything else. Well, except for a tree.

It is not in my nature to decline a free giveaway, so when the gentlemen at the tree lot offered scrap trimmings (all I could cart away!), and my spouse was preoccupied with tying the tree to the car’s roof, I grabbed an armload. I kept them in a bucket of water on the deck until I discerned a future for them.

Yesterday, armed with a paddle of florist’s wire and a pair of hand pruners, I crafted a garland for our mailbox.

mailbox left profile full view

It began as an 8-foot-long rope of Fraser fir (Abies fraseri), wired together from cuttings 18 inches long or so, and annotated with silver wired ribbon. But it suffered acute dullness.

Pondering what might give it some verve, I remembered the cardinal rule to add texture. And what luck; I have never, in the ten years I’ve lived here, conquered the English ivy (Hedera helix) that I inherited on closing day. So I yanked up a few yards’ worth and tucked them in amidst the fir. In the winter, the marbling of the leaves seems more pronounced.

A march around the garden yielded leaves of Magnolia grandiflora, seedlings of privet (Ligustrum) and loblolly pine (Pinus taeda), and clippings of Nandina domestica‘s leaves and berries.

mailbox right profile detail

I uprooted an entire plant of Artemisia ‘Powis Castle’ that has never done well. Off with its evergreen heads, and into the mix they went. They drooped quickly, but no one driving by will notice.

mailbox left profile detail

Not bad for compost-in-waiting, I think.

Seed viability, part 3: Planting seedlings embedded in paper toweling

The easy sprouts have been potted up, and now it is time to tackle the ingrown ones.

seedlings embedded in towel

Now, the good thing about seedlings growing through their germinating substrate (the paper towel) is that, if you can be trusted with a pair of scissors and have sharp ones to hand (does anyone besides tailors ever have sharp scissors?), you can trim yourself a little seed mat by which to handle the seedling, making transplanting relatively risk-free. Or you can use a box cutter, if you have a sharp blade and clean it first with a bit of rubbing alcohol.

How to Pot Up Seedlings That Have Grown Through Paper Towels

1. As before, prepare a seed flat with moistened, sterile seed-starting mixture. This flat, incidentally, is an upcycled Chinese food take-out container, and it is perfect for such a task.

prepared seed flat

2. Taking care not to cut off the root (which may have tiny root hairs emerging from it), guide the blade of the knife or scissors between the sprouted seeds. Cut a small section of towel to support the seedling:

seedling embedded in paper towel

3. Carefully cut individual seed mats out of the towel. Hold the towel up to a light to help you find the space between the roots.

hold up the seeds to the light

4. Plant the seedlings, giving adequate space to each one. Don’t overcrowd the flat. Gently firm the roots against the soil.

fully planted seed flat

The seed capsules on the soil surface fell off during the planting process. These are not additional, fresh seeds planted in the flat, which would overcrowd the plants.

5. Top the seedlings off with fresh seed-starting mix, up to the base of the seed leaves.

top-dressed flat

6. Water gently, using a rose on a watering can or the spray function of a faucet or squirt bottle, and set in a bright, warm space.

Keep an eye on the seedlings, in whatever form they were potted up, and do not allow them to dry out. Bottom-watering is best: Set the flat in a shallow dish of water and allow the water to wick up through the drainage holes in the bottom of the flat. Once the seedlings have developed one or two sets of true leaves, they may be potted up again.

Cold frames

Welcome back, gardening friends! I hope you had a wonderful holiday season and a happy new year.

The deep freeze that has hit most of the eastern half of the United States has just found its way to me. Fortunately, over the long holiday break, I took advantage of some warmish weather to repair my cold frame, which took a bit of a beating during the recent home renovation.

A cold frame is a simple enclosure with a clear or translucent roof that is used to shelter plants from cold or otherwise inclement weather. It is similar to a greenhouse, only generally less grand, and specifically, unheated. It can sit low to the ground or even be dug into the ground. It can shelter pots or can be planted directly, depending on the user’s needs.

I built mine out of recycled materials three years ago. It is a simple wooden box, measuring 8 feet long by 3 feet wide, and slopes from 20 inches tall at the back to 15 inches in the front.cold frame

Because the area where it is located contains the main electricity line to the house, the box sits on the surface, atop of a thick layer of gravel. In a colder climate, I might dig the cold frame into the ground, but it seldom stays very cold here for long.

The frame windows are upcycled window sashes from the Habitat for Humanity ReStore.

pots of greens in the cold frameIn the past, I lined the perimeter of the frames with foam weatherstripping, which does a good job of keeping out the cold air. However, it becomes brittle after a season and must be replaced annually.

The white-painted interior reflects light to the plants inside. The cold frame faces south, but tall trees to the southeast block some sun, even in the winter. (I’ll paint the outside to match the house when the weather warms up.) The cold frame does an excellent job of sheltering  tender plants, like my salad bowl garden. It also keeps my worm composting bin frost-free, allowing the worms to continue their good work, albeit more slowly, in the coldest months.

broken window panes on my cold frame

One of the window sashes was damaged during the renovation and must be replaced. I have been slow to fix it because its sorry state has spared me from having to vent the box during the warmest part of the day. I cannot replace the window today, but with overnight temperatures expected in the single digits Fahrenheit (that’s very cold for here), I need to make some arrangements to compensate for the heat loss the broken window allows.

First, I’ve crowded my plants together tightly in the section furthest away from the broken window. Reducing the gaps where frigid air can circulate will help the plants survive. I’m moving a few of my winter sowing seed pans and cuttings into the frame as extra insurance, though that does go against the philosophy of winter sowing.

crowded pots in the cold frame

Next, I took a few old shopping bags from my shed, filled them with dry leaves, and tied the handles closed. I tucked these in amongst the plants inside the frame. These will act as makeshift insulation batts, sheltering the plants from any drafts.

Third, I cut a double-thickness section of 3.5-mil translucent plastic sheeting to fit the window frame and stapled it into place, to help compensate for the broken panes of glass.

A double thickness of 3.5 mil plastic sheeting compensates for the broken glass panes.

Finally, below the window sashes but above the plants, I added a layer of that same 3.5 mil plastic sheeting and some cardboard before it goes to the recycling. This should stop most of the cold from penetrating the broken window.

cold frame put to bed

I know my northern neighbors are coping with much worse weather, and my thoughts are with you all. Stay warm and safe!

Homemade composter: Upcycled pickle barrel

I have never met a gardener who believed she had enough compost.

English: A picture of compost soil

English: A picture of compost soil (Photo credit: Wikipedia)

In the past, I have generated my compost in homemade bins made of 2x lumber and window screening, chicken wire, or whatever materials I had to hand. Those enclosures work well enough, but of course compost does take time.

I have always eyed those compost tumblers in gardening supply catalogues and wondered if they work as well as they allege. When I happened across a design for a homemade compost tumbler, from the blog Potholes and Pantyhose, I recognized a golden opportunity.

It was an especially fortuitous discovery because I happened to have most of the materials on hand.

Some years ago I obtained four pickle barrels off of Craigslist (about $15 apiece) with the intention of creating four rain barrels. I successfully made three. The fourth barrel had a lid that would not come off, no matter how we tried. It sat behind our shed until now, waiting for its opportunity to serve. I also had lumber and most of the necessary hardware, including a discarded metal closet rod that would serve beautifully as the tumbler axis.

homemade compost tumbler

The instructions at Potholes and Pantyhose are straightforward enough.  I found that the window latch hardware was insufficient to hold the lid closed, though, so I used a T-hasp closure instead (yes, that’s a stick stuck through the closure).

I’ve placed the tumbler next to my regular compost pile. Every time I go out to the pile, I give the tumbler a few spins (the kids also like to give it a whirl, which only accelerates the decomposition). Kitchen scraps, weeds, and newspaper go into the tumbler, while larger garden debris and shredded leaves and twigs go into the pile.

So far, it’s working brilliantly.